Industry Best Practice is best achieved by using the IfSQ Level-3 Standard, Industry Best Practice for Computer Program Source Code. Software which complies with the standard is is more likely to be error-free, is easier to debug, and much less expensive to modify than non-compliant software.
A Level-3 Assessment takes about 5 minutes per page and can be performed by a team of two programmers who have both completed the IfSQ Level-3 Assessment Course, one of whom has at least two years experience in the language in which the program is written. The following research findings influenced the content of the standard:
- A study of 450 routines found that 50 percent of highly cohesive programs were fault free, compared to only 18 percent of routines with low cohesion.
- Given a sample of 450 routines, the routines with the highest coupling-to-cohesion ratios had 7 times more errors than those with the lowest ratios.
- Routines with low cohesion can cost 20 times more to fix than fixing highly cohesive routines.
- The effort required to debug a program is minimized when variables had names averaging 10 to 16 characters long.
- 46 percent of routines with no unused variables had no errors compared to only 17 to 29 percent for those with one or more unreferenced variables.
- Large programs that use information hiding are a factor 4 easier to modify than programs which don't.