Most of the stuff that I've read on investing (particularly on value investing) has example strategies like : long the stocks in a certain percentile range of some parameter and short the ones in another percentile range. For example, a momentum strategy would be like: short the top decile of winners and bottom decile of losers (which could mean the stocks having highest 10% or lowest 10% of past year returns). Or a strategy based on some fundamental ratio like P/BV is usually phrased as: long the bottom quintile of stocks (lowest 20% of P/BV values), etc.
That's great, but I'm wondering how to interpret such strategies for implementation. Most strategy descriptions (at least that I've read) only state which stocks to go long/short in, but not what actual weight to assign to them. The trivial case would be to have an equally-weighted portfolio, but I'm not convinced that that's likely to work most of the time. Is the weight implicit in such descriptions? Is there a way to determine the appropriate weight to assign to various stocks, given the description of the filter?