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Steve McConnell’s Classic Software Mistakes Revisited

In chapter 3 of Rapid Development, Steve McConnell identified 36 “classic software mistakes.” That book was published in 1996 and a lot has changed since then. So I was happy to learn that he released a white paper that expanded and updated the list.

The new list was validated with a survey of about 500 software professionals. The data gathered from the survey allowed McConnell and rank the list, which makes it much more valuable.

Read on to find out which software development practices are actually the worst “classic software mistakes.”

What is a “classic software mistake”?

McConnell defined “classic mistakes” as follows:

Some ineffective development practices have been chosen so often, by so many people, with such predictable, bad results that they deserve to be called “classic mistakes.”

Falling victim to even one of these “classic software mistakes” can condemn your project to slow, expensive development. You need to avoid all of them if you want to be efficient. The top 20 mistakes are especially damaging.

What are the new “classic software mistakes”?

The following table shows the software mistakes ranked by how often they occur multiplied by the average severity of the impact of the mistake when it does occur. This gives us a “mistake exposure index.”

While you want to avoid all the “classic software mistakes,” the mistakes with a higher “mistake exposure index” will be more damaging to your project than mistakes with a lower score.

table of 42 classic software mistakes

Additional Resources:

You can download the white paper (which contains many more details) from Steve’s website.

Wrapping Up

This updated list of “classic software mistakes” is much more useful than the original list for two reasons.

First, it’s much more recent (2008). So you can assume that the software development practices used by the survey respondents are closer to the kind of software development you do (as compared to the original list, which was published in 1996).

Secondly, with the addition of the survey data, McConnell was able to produce a ranking of the potential impact on project success of each mistake (the original list was unordered).

With this information in hand, you’ll have a better idea of which mistakes are likely slowing down your development efforts the most.

2 Comments

  1. Michael Best

    This other blog post mentions the classic mistakes and also Capers Jones (Geriatric Issues of Ageing Software 2007, Estimating Software Costs 2008) has found that staffing a maintenance team with inexperienced people destroys productivity and is one of the worst practices that any organization can follow. https://dzone.com/articles/classic-mistakes-software From 2006 The Economics of Software Maintenance In The Twenty first Century https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.88.7697&rep=rep1&type=pdf

    • Blaine Osepchuk

      Wow! Great links. The second link points to a particularly good paper on the factors that influence the cost of software maintenance.

      Thanks for sharing this information.

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