Why you don't believe in short term trading or day trading?

Predicting the market for the short term is almost impossible; there are no tools with acceptable certainty that can do so. Charts and technical analysis tell what happened in the past and try to project that into the future. History tends to repeat itself but at random certainty, and basing your investment decision on this will result in random profitability or loss. Predicting the future of a company's performance is closer to science than that of technical analysis thus it stands better chances for success.