Very inspirational book for trade traders: https://books.google.com/books/about/The_Rule.html?id=BVWsDwAAQBAJ&source=kp_book_description The Rule: How I Beat the Odds in the Markets and in Life—and How You Can Too, by Larry Hite
No need to read a book, unless it is a book on statistics. You stated that your are using a 4 hour chart for trend and a 1 hour chart for pattern but want to know how far back to look on your 4 hour chart. You are most likely applying some indicator or trendline to the 4 hour chart and finding that it will switch directions depending on your look back period. If the above is correct then try something like... https://c.mql5.com/forextsd/forum/221/TASC-Set-2010-Getting-Clear-With-Short-Term-Swings__1.pdf Otherwise as @wrbtrader stated your question is too vague.... One 4 hour bar will not show a trend Two 4 hour bars might show higher highs and higher lows (the definition of a trend) but it also might be one bar followed by an inside bar or outside bar and not show a trend. The inside bar outside bar can scenario can continue for three or even four bars or even more. Most people will just plot an indicator or trendline with a fixed lookback (for trend) and then apply a pattern for entry. Regardless of how many 1 hour or 4 hour bars you use or what indicator you are applying to them or what the look back period on the indicator/trendline is for determining the trend, you are ultimately going to have to get statistics on whether they provide a positive expectancy with your entry pattern. And then analyze those statistics to make sure you are not curve fitting a system/method, which is a different matter. Anyway, if you cant get any good stats by doing these it might be your entry pattern that's sucks. Good luck