I discovered that one of the best ways to measure how well a company is growing, especially private companies that don't disclose information easily, is to follow how many open roles they have on their careers page. As a Software Engineer I used this to avoid companies that were hiring but were on a downward hiring trajectory, and subsequently were doing poorly as a startup. I also used this as supplemental analysis to a Palantir trade I opened when the stock was at $9. And I'm now using this approach again to look for my next job opportunity, except I've built an app that allows others to do the same easily.
Comment below if you'd like to see a top tech startup tracked on careertrends.io