Blue Club does not specify use of the Losing Trick Count, but it is the best way to quickly estimate the trick taking power of a hand, assuming an 8 card fit has been found.
Losers are counted in each suit, and totalled for the hand.
The total is the number of losers in your hand, the fewer the better.
It's common to make the following adjustments:
A 1-level suit opening requires at most 7 losers; 1C openings generally have 5 or less.
The losers in both hands are totalled, and the result subtracted from 18; this gives the level to which you can confidently raise.
For example if responder has 8 losers and 4 card support for a 1-level opening, he can raise to the 3 level; if opener has 6 losers rather than the expected 7, he can continue toward game.
Considering its simplicity, the Losing Trick Count is remarkably reliable up to the level of 4 or perhaps 5; beyond that posession of first and second round controls, and considerations of shape, become more important.