Tomas Tunguz is a venture capitalist at Redpoint Ventures.  In this article, Tunguz discusses why negative churn is the highest correlated factor to post-money series A valuations for SaaS companies.

The Leading Predictor of Series A Valuation for SaaS Companies

The highest correlated factor to post-money valuations for Series A SaaS companies isn’t revenue or revenue growth, but negative churn. Revenue growth correlates to post-money with a 0.18 R^2. Revenue correlates at 0.3 R^2. Negative churn, or account expansion, correlates at 0.54 R^2.