> We've known since the early sixties, but have never come to grips with the implications that there are net negative producing programmers (NNPPs) on almost all projects, who insert enough spoilage to exceed the value of their production. So, it is important to make the bold statement: Taking a poor performer off the team can often be more productive than adding a good one. [6, p. 208] Although important, it is difficult to deal with the NNPP. Most development managers do not handle negative aspects of their programming staff well. This paper discusses how to recognize NNPPs, and remedial actions necessary for project success.
> Researchers have found between a low of 5 to 1 to a high of 100 to 1 ratios in programmer performance. This means that programmers at the same level, with similar backgrounds and comparable salaries, might take 1 to 100 weeks to complete the same tasks. [21, p. 8]
Source 21 is: Shneiderman, Ben Software Psychology: Human Factors in Computer and Information Systems (Cambridge, MA: Winthrop, 1980)
There are some programmers who are worse than nothing happening. So a 10x looks better by working accords the averages of all the 1x, -1x, etc.