More recent tests, both cross-sectional and time series, find that variables such as size, earnings to price, debt to equity, and the book-to-market ratio (B/M) provide explanatory power not captured by beta. These studies confirm the now-recognized empirical flaws in both the Sharpe-Linter and the Black versions of the CAPM. Behavioralists interpret the results as evidence of irrational pricing caused by investor overreaction. The rational pricing interpretation is that a more sophisticated asset-pricing model is needed.