Computer scientist Matt Welsh said that one reason he left Harvard for Google was that he was spending 40% of his time chasing grants. At Google, he devotes all his time to doing computer science. Here’s how he describes it in his blog post The Secret Lives of Professors:
The biggest surprise is how much time I have to spend getting funding for my research. Although it varies a lot, I guess that I spent about 40% of my time chasing after funding, either directly (writing grant proposals) or indirectly (visiting companies, giving talks, building relationships). It is a huge investment of time that does not always contribute directly to your research agenda—just something you have to do to keep the wheels turning.
According to this Scientific American editorial, 40% is typical.
Most scientists finance their laboratories (and often even their own salaries) by applying to government agencies and private foundations for grants. The process has become a major time sink. In 2007 a U.S. government study found that university faculty members spend about 40 percent of their research time navigating the bureaucratic labyrinth, and the situation is no better in Europe.
Not only do scientists on average spend a large amount of time pursuing grants, they tend to spend more time on grants as their career advances. (This has an element of tautology: you advance your career in part by obtaining grants, so the most successful are the ones who have secured the most grant money.)
By the time scientists are famous, they may no longer spend much time actually doing science. They may spend nearly all their research time chasing grants either directly or, as Matt Welsh describes, indirectly by traveling, speaking, and schmoozing.