Right now, I have a list of 20 stocks that I simply compare against the S&P/Nasdaq. I would like to expand the list so that, intraday, I short only the weakest and buy only the strongest.
depends on what your criteria for "strongest" and "weakest" is. once you figure it out, i would go enter it at www.stockfetcher.com and scan there.
This method has been very accurate as of late: Write the symbol for each stock you are interested in on a 3x5 card. Stack the cards. Throw the stack, as hard as you can, against the ceiling. The cards that stick to the ceiling have the strong stocks. The cards of weak stocks are the ones that fall to the floor.
If you can't decide by looking through 20 6 month charts you shouldn't be trading. Here is a clue . If the prices slope upward to the right they might be stronger than those that slope downward to the right.