Scale in or scale out

If you were given only two choices, would you elect to scale into a trade or out of a trade? i.e. Which of the two do you believe gives you more of an edge?

One strategy is to do "position improvement" which is best explained by an example. Say you go long and the market drops, you then double your position (say) 2 points below where you entered and put in a limit order to exit your original position at the entry with your stop 2 points below the second entry for a max loss of 4 points which is really a loss of 3 points against the whole position.