Why do companies fix faults in software they sell?
Once I buy some software from a company they have my money, if sometime later I find a fault software what incentive does that company have to fix the software and provide me with an update (assuming the software is not so fault ridden that I take advantage of laws allowing me to return a purchase for a refund)?
There are three economic incentives for companies to fix faults:
- because I am paying them a fee for updates that include fixes to known faults,
- because they want to make future sales to me and to others (faults encountered by customers contribute towards the perception of product quality),
- they don’t want to loose money because a fault had consequences that resulted in legal action (this reason is overhyped, in practice software engineering has a missing dead body problem).
Which faults get fixed? Software is surprisingly fault tolerant and there is no point in fixing faults that customers are unlikely to encounter. This means that once a product has been released and known to be acceptable to many customers there is no incentive to actively search for faults; this means that the only faults likely to be fixed are the ones reported by customers.
When reporting a fault customers are often asked to rate its severity. This is a useful technique for prioritizing what gets fixed first or perhaps what does not get fixed at all. Customers who actively set out to find faults are not appreciated and are labeled as disruptive if they continue doing it. Finding faults is surprisingly easy, finding the faults that have a high probability of being encountered by customers and ranked by them as critical is very hard (this is one of the reasons static analysis tools are not widely used).
What is the motivation for developers to fix faults in Open Source?
- There are companies who provide support services for a fee, just like commercial offerings,
- Open Source is free, gaining more users is not an obvious incentive to fix faults. However, being known as the go-to guys for a given package is a way of attracting companies looking to hire somebody to provide support services or make custom modifications to that package. Fixing faults is a way of getting visibility, it is advertising.
- Developers hate the thought of doing something wrong resulting in a fault in code they have written and writing faulty code is not socially acceptable behavior in software development circles. These feelings about what constitutes appropriate behavior are often enough to make developers want to spend time fixing faults in code they have written or feel responsible for, provided they have the time. I suspect a lot of faults get fixed by developers when their manager/wife thinks they are working on something more ‘useful’.