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How to be a Programmer (chapter 3)

Chapter 3. Intermediate Personal Skills How to Stay Motivated It is a wonderful and surprising fact that programmers are highly motivated by the desire to create artifacts tha...
Views: 1.810 Created 04/09/2007

Chapter 3. Intermediate

Personal Skills

How to Stay Motivated

It is a wonderful and surprising fact that programmers are highly motivated by the desire to create artifacts that are beautiful, useful, or nifty. This desire is not unique to programmers nor universal but it is so strong and common among programmers that it separates them from others in other roles.

This has practical and important consequences. If programmers are asked to do something that is not beautiful, useful, or nifty, they will have low morale. There's a lot of money to be made doing ugly, stupid, and boring stuff; but in the end, fun will make the most money for the company.

Obviously, there are entire industries organized around motivational techniques some of which apply here. The things that are specific to programming that I can identify are:

  • Use the best language for the job.

  • Look for opportunities to apply new techniques, languages, and technologies.

  • Try to either learn or teach something, however small, in each project.

Finally, if possible, measure the impact of your work in terms of something that will be personally motivating. For example, when fixing bugs, counting the number of bugs that I have fixed is not at all motivational to me, because it is independent of the number that may still exist, and is also affects the total value I'm adding to my company's customers in only the smallest possible way. Relating each bug to a happy customer, however, is personally motivating to me.

How to be Widely Trusted

To be trusted you must be trustworthy. You must also be visible. If know one knows about you, no trust will be invested in you. With those close to you, such as your teammates, this should not be an issue. You establish trust by being responsive and informative to those outside your department or team. Occasionally someone will abuse this trust, and ask for unreasonable favors. Don't be afraid of this, just explain what you would have to give up doing to perform the favor.

Don't pretend to know something that you don't. With people that are not teammates, you may have to make a clear distinction between ``not knowing right off the top of my head'' and ``not being able to figure it out, ever.''

How to Tradeoff Time vs. Space

You can be a good programmer without going to college, but you can't be a good intermediate programmer without knowing basic computational complexity theory. You don't need to know ``big O'' notation, but I personally think you should be able to understand the difference between ``constant-time'',``n log n'' and ``n squared''. You might be able to intuit how to tradeoff time against space without this knowledge, but in its absence you will not have a firm basis for communicating with your colleagues.

In designing or understanding an algorithm, the amount of time it takes to run is sometimes a function of the size of the input. When that is true, we can say an algorithm's worst/expected/best-case running time is ``n log n'' if it is proportional to the size ($n$) times the logarithm of the size. The notation and way of speaking can be also be applied to the space taken up by a data structure.

To me, computational complexity theory is beautiful and as profound as physics---and a little bit goes a long way!

Time (processor cycles) and space (memory) can be traded off against each other. Engineering is about compromise, and this is a fine example. It is not always systematic. In general, however, one can save space by encoding things more tightly, at the expense of more computation time when you have to decode them. You can save time by caching, that is, spending space to store a local copy of something, at the expense of having to maintain the consistency of the cache. You can sometimes save time by maintaining more information in a data structure. This usually cost a small amount of space but may complicate the algorithm.

Improving the space/time tradeoff can often change one or the other dramatically. However, before you work on this you should ask yourself if what you are improving is really the thing that needs the most improvement. It's fun to work on an algorithm, but you can't let that blind you to the cold hard fact that improving something that is not a problem will not make any noticeable difference and will create a test burden.

Memory on modern computers appears cheap, because unlike processor time, you can't see it being used until you hit the wall; but then failure is catastrophic. There are also other hidden costs to using memory, such as your effect on other programs that must be resident, and the time to allocate and deallocate it. Consider this carefully before you trade away space to gain speed.

How to Stress Test

Stress testing is fun. At first it appears that the purpose of stress testing is to find out if the system works under a load. In reality, it is common that the system does work under a load but fails to work in some way when the load is heavy enough. I call this hitting the wall or bonking[1]. There may be some exceptions, but there is almost always a ‘wall’. The purpose of stress testing is to figure out where the wall is, and then figure out how to move the wall further out.

A plan for stress testing should be developed early in the project, because it often helps to clarify exactly what is expected. Is two seconds for a web page request a miserable failure or a smashing success? Is 500 concurrent users enough? That, of course, depends, but one must know the answer when designing the system that answers the request. The stress test needs to model reality well enough to be useful. It isn't really possible to simulate 500 erratic and unpredictable humans using a system concurrently very easily, but one can at least create 500 simulations and try to model some part of what they might do.

In stress testing, start out with a light load and load the system along some dimension---such as input rate or input size---until you hit the wall. If the wall is too close to satisfy your needs, figure out which resource is the bottleneck (there is usually a dominant one.) Is it memory, processor, I/O, network bandwidth, or data contention? Then figure out how you can move the wall. Note that moving the wall, that is, increasing the maximum load the system can handle, might not help or might actually hurt the performance of a lightly loaded system. Usually performance under heavy load is more important than performance under a light load.

You may have to get visibility into several different dimensions to build up a mental model of it; no single technique is sufficient. For instance, logging often gives a good idea of the wall-clock time between two events in the system, but unless carefully constructed, doesn't give visibility into memory utilization or even data structure size. Similarly, in a modern system, a number of computers and many software systems may be cooperating. Particularly when you are hitting the wall (that is, the performance is non-linear in the size of the input) these other software systems may be a bottleneck. Visibility into these systems, even if only measuring the processor load on all participating machines, can be very helpful.

Knowing where the wall is is essential not only to moving the wall, but also to providing predictability so that the business can be managed effectively.

How to Balance Brevity and Abstraction

Abstraction is key to programming. You should carefully choose how abstract you need to be. Beginning programmers in their enthusiasm often create more abstraction than is really useful. One sign of this is if you create classes that don't really contain any code and don't really do anything except serve to abstract something. The attraction of this is understandable but the value of code brevity must be measured against the value of abstraction. Occasionally, one sees a mistake made by enthusiastic idealists: at the start of the project a lot of classes are defined that seem wonderfully abstract and one may speculate that they will handle every eventuality that may arise. As the project progresses and fatigue sets in, the code itself becomes messy. Function bodies become longer than they should be. The empty classes are a burden to document that is ignored when under pressure. The final result would have been better if the energy spent on abstraction had been spent on keeping things short and simple. This is a form of speculative programming. I strongly recommend the article ``Succinctness is Power'' by Paul Graham[PGSite].

There is a certain dogma associated with useful techniques such as information hiding and object oriented programming that are sometimes taken too far. These techniques let one code abstractly and anticipate change. I personally think, however, that you should not produce much speculative code. For example, it is an accepted style to hide an integer variable on an object behind mutators and accessors, so that the variable itself is not exposed, only the little interface to it. This does allow the implementation of that variable to be changed without affecting the calling code, and is perhaps appropriate to a library writer who must publish a very stable API. But I don't think the benefit of this outweighs the cost of the wordiness of it when my team owns the calling code and hence can recode the caller as easily as the called. Four or five extra lines of code is a heavy price to pay for this speculative benefit.

Portability poses a similar problem. Should code be portable to a different computer, compiler, software system or platform, or simply easily ported? I think a non-portable, short-and-easily-ported piece of code is better than a long portable one. It is relatively easy and certainly a good idea to confine non-portable code to designated areas, such as a class that makes database queries that are specific to a given DBMS.

How to Learn New Skills

Learning new skills, especially non-technical ones, is the greatest fun of all. Most companies would have better morale if they understood how much this motivates programmers.

Humans learn by doing. Book-reading and class-taking are useful. But could you have any respect for a programmer who had never written a program? To learn any skill, you have to put yourself in a forgiving position where you can exercise that skill. When learning a new programming language, try to do a small project it in before you have to do a large project. When learning to manage a software project, try to manage a small one first.

A good mentor is no replacement for doing things yourself, but is a lot better than a book. What can you offer a potential mentor in exchange for their knowledge? At a minimum, you should offer to study hard so their time won't be wasted.

Try to get your boss to let you have formal training, but understand that it often not much better than the same amount of time spent simply playing with the new skill you want to learn. It is, however, easier to ask for training than playtime in our imperfect world, even though a lot of formal training is just sleeping through lectures waiting for the dinner party.

If you lead people, understand how they learn and assist them by assigning them projects that are the right size and that exercise skills they are interested in. Don't forget that the most important skills for a programmer are not the technical ones. Give your people a chance to play and practice courage, honesty, and communication.

Learn to Type

Learn to touch-type. This is an intermediate skill because writing code is so hard that the speed at which you can type is irrelevant and can't put much of a dent in the time it takes to write code, no matter how good you are. However, by the time you are an intermediate programmer you will probably spend a lot of time writing natural language to your colleagues and others. This is a fun test of your commitment; it takes dedicated time that is not much fun to learn something like that. Legend has it that when Michael Tiemann[2] was at MCC people would stand outside his door to listen to the hum generated by his keystrokes which were so rapid as to be indistinguishable.

How to Do Integration Testing

Integration testing is the testing of the integration of various components that have been unit tested. Integration is expensive and it comes out in the testing. You must include time for this in your estimates and your schedule.

Ideally you should organize a project so that there is not a phase at the end where integration must explicitly take place. It is far better to gradually integrate things as they are completed over the course of the project. If it is unavoidable estimate it carefully.

Communication Languages

There are some languages, that is, formally defined syntactic systems, that are not programming languages but communication languages---they are designed specifically to facillitate communication through standardization. In 2003 the most important of these are UML, XML, and SQL. You should have some familiarity with all of these so that you can communicate well and decide when to use them.

UML is a rich formal system for making drawings that describe designs. It's beauty lines in that is both visual and formal, capable of conveying a great deal of information if both the author and the audience know UML. You need to know about it because designs are sometimes communicated in it. There are very helpful tools for making UML drawings that look very professional. In a lot of cases UML is too formal, and I find myself using a simpler boxes and arrows style for design drawings. But I'm fairly sure UML is at least as good for you as studying Latin.

XML is a standard for defining new standards. It is not a solution to data interchange problems, though you sometimes see it presented as if it was. Rather, it is a welcome automation of the most boring part of data interchange, namely, structuring the representation into a linear sequence and parsing back into a structure. It provides some nice type- and correctness-checking, though again only a fraction of what you are likely to need in practicen.

SQL is a very powerful and rich data query and manipulation language that is not quite a programming language. It has many variations, typically quite product-dependent, which are less important than the standardized core. SQL is the lingua franca of relational databases. You may or may not work in any field that can benefit from an understanding of relational databases, but you should have a basic understanding of them and they syntax and meaning of SQL.

Heavy Tools

As our technological culture progresses, software technology moves from inconceivable, to research, to new products, to standardized products, to widely available and inexpensive products. These heavy tools can pull great loads, but can be intimidating and require a large investment in understanding. The intermediate programmer has to know how to manage them and when they should be used or considered.

To my mind right some of the best heavy tools are:

  • Relational Databases,

  • Full-text Search Engines,

  • Math libraries,

  • OpenGL,

  • XML parsers, and

  • Spreadsheets.


How to analyze data


Data analysis is a process in the early stages of software development, when you examine a business activity and find the requirements to convert it into a software application. This is a formal definition, which may lead you to believe that data analysis is an action that you should better leave to the systems analysts, while you, the programmer, should focus on coding what somebody else has designed. If we follow strictly the software engineering paradigm, it may be correct. Experienced programmers become designers and the sharpest designers become business analysts, thus being entitled to think about all the data requirements and give you a well defined task to carry out. This is not entirely accurate, because data is the core value of every programming activity. Whatever you do in your programs, you are either moving around or modifying data. The business analyst is analyzing the needs in a larger scale, and the software designer is further squeezing such scale so that, when the problem lands on your desk, it seems that all you need to do is to apply clever algorithms and start moving existing data.

Not so.

No matter at which stage you start looking at it, data is the main concern of a well designed application. If you look closely at how a business analyst gets the requirements out of the customer?s requests, you?ll realize that data plays a fundamental role. The analyst creates so called Data Flow Diagrams, where all data sources are identified and the flow of information is shaped. Having clearly defined which data should be part of the system, the designer will shape up the data sources, in terms of database relations, data exchange protocols, and file formats, so that the task is ready to be passed down to the programmer. However, the process is not over yet, because you ? the programmer ? even after this thorough process of data refinement, are required to analyze data to perform the task in the best possible way. The bottom line of your task is the core message of Niklaus Wirth, the father of several languages. ?Algorithms + Data Structures = Programs.? There is never an algorithm standing alone, doing something to itself. Every algorithm is supposed to do something to at least one piece of data.

Therefore, since algorithms don't spin their wheels in a vacuum, you need to analyze both the data that somebody else has identified for you and the data that is necessary to write down your code. A trivial example will make the matter clearer. You are implementing a search routine for a library. According to your specifications, the user can select books by a combination of genre, author, title, publisher, printing year, and number of pages. The ultimate goal of your routine is to produce a legal SQL statement to search the back-end database. Based on these requirements, you have several choices: check each control in turn, using a "switch" statement, or several "if" ones; make an array of data controls, checking each element to see if it is set; create (or use) an abstract control object from which inherit all your specific controls, and connect them to an event-driven engine. If your requirements include also tuning up the query performance, by making sure that the items are checked in a specific order, you may consider using a tree of components to build your SQL statement. As you can see, the choice of the algorithm depends on the data you decide to use, or to create. Such decisions can make all the difference between an efficient algorithm and a disastrous one. However, efficiency is not the only concern. You may use a dozen named variables in your code and make it as efficient as it can ever be. But such a piece of code might not be easily maintainable. Perhaps choosing an appropriate container for your variables could keep the same speed and in addition allow your colleagues to understand the code better when they look at it next year. Furthermore, choosing a well defined data structure may allow them to extend the functionality of your code without rewriting it. In the long run, your choices of data determines how long your code will survive after you are finished with it. Let me give you another example, just some more food for thought. Let's suppose that your task is to find all the words in a dictionary with more than three anagrams, where an anagram must be another word in the same dictionary. If you think of it as a computational task, you will end up with an endless effort, trying to work out all the combinations of each word and then comparing it to the other words in the list. However, if you analyze the data at hand, you'll realize that each word may be represented by a record containing the word itself and a sorted array of its letters as ID. Armed with such knowledge, finding anagrams means just sorting the list on the additional field and picking up the ones that share the same ID. The brute force algorithm may take several days to run, while the smart one is just a matter of a few seconds. Remember this example the next time you are facing an intractable problem.

Team Skills

How to Manage Development Time

To manage development time, maintain a concise and up-to-date project plan. A project plan is an estimate, a schedule, a set of milestones for marking progress, and an assignment of your team or your own time to each task on the estimate. It should also include other things you have to remember to do, such as meeting with the quality assurance people, preparing documentation, or ordering equipment. If you are on a team, the project plan should be a consensual agreement, both at the start and as you go.

The project plan exists to help make decisions, not to show how organized you are. If the project plan is either too long or not up-to-date, it will be useless for making decisions. In reality, these decisions are about individual persons. The plan and your judgment let you decide if you should shift tasks from one person to another. The milestones mark your progress. If you use a fancy project planning tool, do not be seduced into creating a Big Design Up Front (BDUF) for the project, but use it maintain concision and up-to-dateness.

If you miss a milestone, you should take immediate action such as informing your boss that the scheduled completion of that project has slipped by that amount. The estimate and schedule could never have been perfect to begin with; this creates the illusion that you might be able to make up the days you missed in the latter part of the project. You might. But it is just as likely that you have underestimated that part as that you have overestimated it. Therefore the scheduled completion of the project has already slipped, whether you like it or not.

Make sure you plan includes time for: internal team meetings, demos, documentation, scheduled periodic activities, integration testing, dealing with outsiders, sickness, vacations, maintenance of existing products, and maintenance of the development environment. The project plan can serve as a way to give outsiders or your boss a view into what you or your team is doing. For this reason it should be short and up-to-date.

How to Manage Third-Party Software Risks

A project often depends on software produced by organizations that it does not control. There are great risks associated with third party software that must be recognized by everyone involved.

Never, ever, rest any hopes on vapor. Vapor is any alleged software that has been promised but is not yet available. This is the surest way to go out of business. It is unwise to be merely skeptical of a software company's promise to release a certain product with a certain feature at a certain date; it is far wiser to ignore it completely and forget you ever heard it. Never let it be written down in any documents used by your company.

If third-party software is not vapor, it is still risky, but at least it is a risk that can be tackled. If you are considering using third-party software, you should devote energy early on to evaluating it. People might not like to hear that it will take two weeks or two months to evaluate each of three products for suitability, but it has to be done as early as possible. The cost of integrating cannot be accurately estimated without a proper evaluation.

Understanding the suitability of existing third party software for a particular purpose is very tribal knowledge. It is very subjective and generally resides in experts. You can save a lot of time if you can find those experts. Often times a project will depend on a third-party software system so completely that if the integration fails the project will fail. Express risks like that clearly in writing in the schedule. Try to have a contingency plan, such as another system that can be used or the ability to write the functionality yourself if the risk can't be removed early. Never let a schedule depend on vapor.

How to Manage Consultants

Use consultants, but don't rely on them. They are wonderful people and deserve a great deal of respect. Since they get to see a lot of different projects, they often know more about specific technologies and even programming techniques than you will. The best way to use them is as educators in-house that can teach by example.

However, they usually cannot become part of the team in the same sense that regular employees are, if only because you may not have enough time to learn their strengths and weaknesses. Their financial commitment is much lower. They can move more easily. They may have less to gain if the company does well. Some will be good, some will be average, and some will be bad, but hopefully your selection of consultants will not be as careful as your selection of employees, so you will get more bad ones.

If consultants are going to write code, you must review it carefully as you go along. You cannot get to the end of the a project with the risk of a large block of code that has not been reviewed. This is true of all team members, really, but you will usually have more knowledge of the team members closer to you.

How to Communicate the Right Amount

Carefully consider the cost of a meeting; it costs its duration multiplied by the number of participants. Meetings are sometimes necessary, but smaller is usually better. The quality of communication in small meetings is better, and less time overall is wasted. If any one person is bored at a meeting take this as a sing, that the meeting should be smaller.

Everything possible should be done to encourage informal communication. More useful work is done during lunches with colleagues than during any other time. It is a shame that more companies do not recognize nor support this fact.

How to Disagree Honestly and Get Away with It

Disagreement is a great opportunity to make a good decision, but it should be handled delicately. Hopefully you feel that you have expressed your thoughts adequately and been heard before the decision is made. In that case there is nothing more to say, and you should decide whether you will stand behind the decision even though you disagree with it. If you can support this decision even though you disagree, say so. This shows how valuable you are because you are independent and are not a yes-man, but respectful of the decision and a team player.

Sometimes a decision that you disagree with will be made when the decision makers did not have the full benefit of you opinion. You should then evaluate whether to raise the issue on the basis of the benefit to the company or tribe. If it is a small mistake in your opinion, it may not be worth reconsidering. If it is a large mistake in you opinion, then of course you must present an argument.

Usually, this is not a problem. In some stressful circumstances and with some personality types this can lead to things being taken personally. For instance, some very good programmers lack the confidence needed to challenge a decision even when they have good reason to believe it is wrong. In the worst of circumstances the decision maker is insecure and takes it as a personal challenge to their authority. It is best to remember that in such circumstances people react with the reptilian part of their brains. You should present your argument in private, and try to show how new knowledge changes the basis on which the decision was made.

Whether the decision is reversed or not, you must remember that you will never be able to say ‘I told you so!’ since the alternate decision was fully explored.


How to Tradeoff Quality Against Development Time

Software development is always a compromise between what the project does and getting the project done. But you may be asked to tradeoff quality to speed the deployment of a project in a way that offends your engineering sensibilities or business sensibilities. For example, you may be asked to do something that is a poor software engineering practice and that will lead to a lot of maintenance problems.

If this happens your first responsibility is to inform your team and to clearly explain the cost of the decrease in quality. After all, your understanding of it should be much better than your boss's understanding. Make it clear what is being lost and what is being gained, and at what cost the lost ground will be regained in the next cycle. In this, the visibility provided by a good project plan should be helpful. If the quality tradeoff affects the quality assurance effort, point that out (both to your boss and quality assurance people). If the quality tradeoff will lead to more bugs being reported after the quality assurance period, point that out.

If she still insists you should try to isolate the shoddiness into particular components that you can plan to rewrite or improve in the next cycle. Explain this to your team so that they can plan for it.

NinjaProgrammer at Slashdot sent in this gem:

Remember that a good design will be resillient against poor code implementations. If good interfaces and abstractions exist throughout the code, then the eventual rewrites will be far more painless. If it is hard to write clear code that is hard to fix, consider what is wrong with the core design that is causing this.


How to Manage Software System Dependence

Modern software systems tend to depend on a large number of components that may not be directly under your control. This increases productivity through synergy and reuse. However, each component brings with it some problems:

  • How will you fix bugs in the component?

  • Does the component restrict you to particular hardware or software systems?

  • What will you do if the component fails completely?

It is always best to encapsulate the component in some way so that it is isolated and so that it can be swapped out. If the component proves to be completely unworkable, you may be able to get a different one, but you may have to write your own. Encapsulation is not portability, but it makes porting easier, which is almost as good.

Having the source code for a component decreases the risk by a factor of four. With source code, you can evaluate it easier, debug it easier, find workarounds easier, and make fixes easier. If you make fixes, you should give them to the owner of the component and get the fixes incorporated into an official release; otherwise you will uncomfortably have to maintain an unofficial version .

How to Decide if Software is Too Immature

Using software other people wrote is one of the most effective ways to quickly build a solid system. It should not be discouraged, but the risks associated with it must be examined. One of the biggest risks is the period of bugginess and near inoperability that is often associated with software before it matures, through usage, into a usable product. Before you consider integrating with a software system, whether created in house or by a third party, it is very important to consider if it is really mature enough to be used. Here are ten questions you should ask yourself about it:

  1. Is it vapor? (Promises are very immature).

  2. Is there an accessible body of lore about the software?

  3. Are you the first user?

  4. Is there a strong incentive for continuation?

  5. Has it had a maintenance effort?

  6. Will it survive defection of the current maintainers?

  7. Is there a seasoned alternative at least half as good?

  8. Is it known to your tribe or company?

  9. Is it desirable to your tribe or company?

  10. Can you hire people to work on it even if it is bad?

A little consideration of these criteria demonstrates the great value of well-established free software and open-source software in reducing risk to the entrepreneur.

How to Make a Buy vs. Build Decision

An entrepreneurial company or project that is trying to accomplish something with software has to constantly make so-called buy vs. build decisions. This turn of phrase is unfortunate in two ways: it seems to ignore open-source and free software which is not necessarily bought. Even more importantly, it should perhaps be called an obtain and integrate vs. build here and integrate decision because the cost of integration must be considered. This requires a great combination of business, management, and engineering savvy.

  • How well do your needs match those for which it was designed?

  • What portion of what you buy will you need?

  • What is the cost of evaluating the integration?

  • What is the cost of integration?

  • What is the cost of evaluating the integration?

  • Will buying increase or decrease long term maintenance costs?

  • Will building it put you in a business position you don't want to be in?

You should think twice before building something that is big enough to serve as the basis for an entire other business. Such ideas are often proposed by bright and optimistic people that will have a lot to contribute to your team. If their idea is compelling, you may wish to change your business plan; but do not invest in a solution bigger than your own business without conscious thought.

After considering these questions, you should perhaps prepare two draft project plans, one for building and one for buying. This will force you to consider the integration costs. You should also consider the long term maintenance costs of both solutions. To estimate the integration costs, you will have to do a thorough evaluation of the software before you buy it. If you can't evaluate it, you will assume an unreasonable risk in buying it and you should decide against buying that particular product. If there are several buy decisions under consideration, some energy will have to be spent evaluating each.

How to Grow Professionally

Assume responsibility in excess of your authority. Play the role that you desire. Express appreciation for people's contribution to the success of the larger organization, as well as things as that help you personally.

If you want to become a team leader, instigate the formation of consensus. If you want to become a manager, take responsibility for the schedule. You can usually do this comfortably while working with a leader or a manager, since this frees them up to take greater responsibility. If that is too much to try, do it a little at a time.

Evaluate yourself. If you want to become a better programmer, ask someone you admire how you can become like them. You can also ask your boss, who will know less but have a greater impact on your career.

Plan ways to learn new skills, both the trivial technical kind, like learning a new software system, and the hard social kind, like writing well, by integrating them into your work.

How to Evaluate Interviewees

Evaluating potential employees is not given the energy it deserves. A bad hire, like a bad marriage, is terrible. A significant portion of everyone's energy should be devoted to recruitment, though this is rarely done.

There are different interviewing styles. Some are torturous, designed to put the candidate under a great deal of stress. This serves a very valuable purpose of possibly revealing character flaws and weaknesses under stress. Candidates are no more honest with interviewers than they are with themselves, and the human capacity for self-deception is astonishing.

You should, at a minimum, give the candidate the equivalent of an oral examination on the technical skills for two hours. With practice, you will be able to quickly cover what they know and quickly retract from what they don't know to mark out the boundary. Interviewees will respect this. I have several times heard interviewees say that the quality of the examination was one of their motivations for choosing a company. Good people want to be hired for their skills, not where they worked last or what school they went to or some other inessential characteristic.

In doing this, you should also evaluate their ability to learn, which is far more important than what they know. You should also watch for the whiff of brimstone that is given off by difficult people. You may be able to recognize it by comparing notes after the interview, but in the heat of the interview it is hard to recognize. How well people communicate and work with people is more important than being up on the latest programming language.

A reader has had good luck using a ‘take-home’ test for interviewees. This has the advantage that can uncover the interviewee that can present themselves well but can't really code---and there are many such people. I personally have not tried this technique, but it sounds sensible.

Finally, interviewing is also a process of selling. You should be selling your company or project to the candidate. However, you are talking to a programmer, so don't try to color the truth. Start off with the bad stuff, then finish strong with the good stuff.

How to Know When to Apply Fancy Computer Science

There is a body of knowledge about algorithms, data structures, mathematics, and other gee-whiz stuff that most programmers know about but rarely use. In practice, this wonderful stuff is too complicated and generally unnecessary. There is no point in improving an algorithm when most of your time is spent making inefficient database calls, for instance. An unfortunate amount of programming consists of getting systems to talk to each other and using very simple data structures to build a nice user interface.

When is high technology the appropriate technology? When should you crack a book to get something other than a run-of-the-mill algorithm? It is sometimes useful to do this but it should be evaluated carefully.

The three most important considerations for the potential computer science technique are:

  • Is it well encapsulated so that the risk to other systems is low and the overall increase in complexity and maintenance cost is low?

  • Is the benefit startling (for example, a factor of two in a mature system or a factor of ten in a new system)?

  • Will you be able to test and evaluate it effectively?

If a well-isolated algorithm that uses a slightly fancy algorithm can decrease hardware cost or increase performance by a factor of two across an entire system, then it would be criminal not to consider it. One of the keys to arguing for such an approach is to show that the risk is really quite low, since the proposed technology has probably been well studied, the only issue is the risk of integration. Here a programmer's experience and judgment can truly synergize with the fancy technology to make integration easy.

How to Talk to Non-Engineers

Engineers and programmers in particular are generally recognized by popular culture as being different from other people. This implies that other people are different from us. This is worth bearing in mind when communicating with non-engineers; you should always understand the audience.

Non-engineers are smart, but not as grounded in creating technical things as we are. We make things. They sell things and handle things and count things and manage things, but they are not experts on making things. They are not as good at working together on teams as engineers are (there are no doubt exceptions.)[3] Their social skills are generally as good as or better than engineers in non-team environments, but their work does not always demand that they practice the kind of intimate, precise communication and careful subdivisions of tasks that we do.

Non-engineers may be too eager to please and they may be intimidated by you. Just like us, they may say ‘yes’ without really meaning it to please you or because they are a little scared of you, and then not stand behind their words.

Non-programmers can understand technical things but they do not have the thing that is so hard even for us---technical judgment. They do understand how technology works, but they cannot understand why a certain approach would take three months and another one three days. (After all, programmers are anecdotally horrible at this kind of estimation as well.) This represents a great opportunity to synergize with them.

When talking to your team you will, without thinking, use a sort of shorthand, an abbreviated language that is effective because you will have much shared experience about technology in general and your product in particular. It takes some effort not to use this shorthand with those that don't have that shared experience, especially when members of your own team are present. This vocabulary create a wall between you and those that do not share it, and, even worse, wastes their time.

With your team, the basic assumptions and goals do not need to be restated often, and most conversation focuses on the details. With outsiders, it must be the other way around. They may not understand things you take for granted. Since you take them for granted and don't repeat them, you can leave a conversation with an outsider thinking that you understand each other when really there is a large misunderstanding. You should assume that you will miscommunicate and watch carefully to find this miscommunication. Try to get them to summarize or paraphrase what you are saying to make sure they understand. If you have the opportunity to meet with them often, spend a little bit of time asking if you you are communicating effectively, and how you can do it better. If there is a problem in communication, seek to alter your own practices before becoming frustrated with theirs.

I love working with non-engineers. It provides great opportunities to learn and to teach. You can often lead by example, in terms of the clarity of your communication. Engineers are trained to bring order out of chaos, to bring clarity out of confusion, and non-engineers like this about us. Because we have technical judgment and can usually understand business issues, we can often find a simple solution to a problem.

Often non-engineers propose solutions that they think will make it easier on us out of kindness and a desire to do the right thing, when in fact a much better overall solution exists which can only be seen by synergizing the outsiders view with your technical judgment. I personally like Extreme Programming because it addresses this inefficiency; by marrying the estimation quickly to the idea, it makes it easier to find the idea that is the best combination of cost and benefit.

[1] to hit


This work is licensed under the GNU Free Documentation License.

The original version of this document was written by Robert L. Read without renumeration and dedicated to the programmers of Hire.com.

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