My backtests have shown that when you buy a sector that just issues a buy signal and if you do so against the market, you will end up on average with a neutral position (the market direction is strong, but your sector's opposite direction is helping you). The best is to buy a sector when yo have a sector buy signal. And the best sectors to buy are those with the worst price RS... until shorts have finished to cover. Then, you need to move to the sectors with strong thrust or best ratings
Pascal