I just got injured on a swing trade on a great stock with great ratios. I was convinced it could not go any lower and, of course, it did. Later I noticed that it's Price/Sales ratio was astronomical and so looking back on it, it must have been that the drop was due to the fact it was considered overvalued. Does anybody check/use P/S, P/E or other fundamental ratios as a filter in their swing trading to avoid getting "burned" like this?