I find it sad that this article leaves out the (admittedly unpublished) research on the 10x phenomena, which is described in Peopleware. They consistently found 10x differences between experienced programmers on the same task, with the same tools.

I find that particular research important for three reasons.

1. The 10 fold difference was consistently demonstrated many times.

2. Their research was conducted with professional programmers, in their workplace.

3. They were able to estimate the impact of a number of different factors, and they found that the single biggest impacts were workplace factors. (Ambient noise, dedicated office space, availability of white boards, etc.)

Admittedly they are unable to tease out why the connection exists between the workplace and productivity. Do productive programmers choose good workplaces? Or do good workplaces make programmers more productive? Probably a bit of both.

BUT if you're an employer, go read that book. Then consider your office plan. It is a lot easier to pay for a good workplace for an effective small team than to pay for a less effective larger team. Office space is probably not where you want to scrimp.