We are currently testing a stock screener that we built and want to implement historical ratios in there too - this is working already for all ratios that don't require stock prices (so all fundamental ratios, profit margin, pietroski f-score etc.). We now want to add historical ratios too that require share prices, say basic/diluted EPS, EV/EBITDA etc. The question is now, which stock price to take for the historical period? The one at the beginning of the period, at the end, an average??
If you are curious how it looks already you can check it out here.