Knowing when it's good enough

A business uses cost-benefit analysis as one of its evaluation criteria when deciding whether to pursue an opportunity or not. One concept central to this is the assessment of potential risks. To me there are a few components to risk assessment:

1. Likelihood of the risk materializing. What's the probability of the risk becoming a problem?
2. Potential cost (monetary, compliance or reputation) to mitigate the risk. How much is it going to cost you? This also includes implementing any mitigation strategies.
   

Combined, these factors provide a value to each risk. Risk assessment can be applied in many different areas:

• Managing the risks encountered in a project.
• Understanding the importance of a defect or bug in a system.
• Managing financial assets.
  

For the purposes of this post I'm only going to write about the second item.

What do you do if you find a defect or bug in a system? You evaluate it to determine whether it's a show stopper or whether you can proceed despite it. Creating bug-free software is the ultimate goal but it has cost and time implications. Here's a quote from an article, They Write The Right Stuff, from Fast Company about a specific software system.

This software never crashes. It never needs to be re-booted. This software is bug-free. It is perfect, as perfect as human beings have achieved. Consider these stats: the last three versions of the program -- each 420,000 lines long-had just one error each. The last 11 versions of this software had a total of 17 errors. Commercial programs of equivalent complexity would have 5,000 errors.

The piece of software in question runs the NASA space shuttle. The consequences of failure could result in the deaths of the astronauts, the loss of a multi-billion dollar piece of hardware and many years of setbacks to the space program. Many of the systems we deal with in the business world do not have this level of criticality. In my past jobs I have worked with time sensitive trading systems where 1/2 second delays mean losses in the $10,000's of dollars. On other projects, variances in marketing and market research data were explainable ("Yes, someone did purchase 50 rolls of toilet paper and it skewed the numbers.") We need to understand when something is good enough as it is instead of always trying to be perfect.