on Jane Friedman site:

If you could improve your productivity by adding one step to your writing routine, would you do it?

Whether you write fiction, nonfiction, or memoir, tracking your word count to measure your daily progress benefits all wordsmiths, because tracking can make you a more efficient writer.

One of the foundational lessons in business school comes from Pearson’s Law, first stated by famed statistician Karl Pearson. It says, “That which is measured improves. That which is measured and reported improves exponentially.”

Although this concept is usually applied to balance sheets and production quotas, it also applies to writers. We can’t know what’s working or where we can improve if we don’t have data to learn from, after all. So if you want to meet a deadline, inspire yourself to write more consistently, or just make it to the end of your draft, word count tracking can help you get there. Here are five reasons why.