I was a sofware director at a Fortune 500 company. I had engineers in Silicon Valley, Santa Cruz, Canada, the Netherlands, Russia, UK, Taiwan, and Wuhan (!) China. I also had individual engineers in Romania, Ireland, Portugal and Germany. Since it was already a global company, it was feasible to hire wherever we could find talent. Some of the Russia team moved to Armenia last year when the office in St. Petersburg was closed. We considered other countries like Vietnam since we had Vietnamese-American engineers but this is where we ended up.

Cost was one of multiple variables determining which site we hired at. At the extremes, it was a 10x difference. The higher the salary, the more senior the team. The competition to hire and retain software engineers caused salaries to go up everywhere, but at a faster rate in the low-cost countries. And low-cost countries were our go-to source for new grads. The profiles of say Russia and China universities varied significantly e.g. experience with open source, mathematical rigor, English skills, credentials, initiative, teamwork, and relevant courses.

The core product develpoment was done in the US but over time, other sites took on more product responsibility. In some of the countries, we also wanted to be closer to our customers, in expanding markets.

It's hard to measure quality, productivity and contribution on an individual basis but it was reasonably correlated with salary. There were outliers though.

So geographically-based staffing was complicated.