The measure of up weeks to down weeks is basically tallying the number of weeks a stock or index rose on rising volume and the number it fell on rising volume. The idea is to get a rough idea of whether money is moving into a stock or out of a stock. Often when stocks base they get quiet both in price moves and in volume after the initial sell off. It is difficult in such lazy action to ascertain day to day whether money is moving in or out. Thus we look at the weekly charts to show us whether there is net buying or selling of the stock. If a stock gets to the end of the base and there are more down weeks on rising volume then that is a good indication that money was most likely moving out of the stock during the base. You will often see these stocks move up to breakout and then fold. The few that were buying and drove the price higher were not enough; once demand was sated the bid left and the stock falls. Often it never even makes the breakout attempt.
Your question goes to the duration of a base. We look at accumulation/distribution on a base basis. Stocks tend to form patterns that can be accumulation or distribution patterns. We count the weeks to ascertain if there truly is accumulation or distribution. Typically the shortest a base can be to weed out the sellers is in the neighborhood of 7 weeks. Not set in stone, but much shorter and it is not really a base but more of a test of another move or simply just not enough time has elapsed to really get rid of the overhead supply. That is the key to any base, getting rid of the easy sellers that bought in at the last high and want to get out ‘even.’ Those have to be removed or so overwhelmed by the buyers that they are swept away in the buying.
Thus we look for roughly seven weeks of basing and count them up to see which is greater. A simple majority is all it takes, but it is always good to see really strong accumulation in conjunction with other indicators. The idea of technical analysis it to give you an edge. Thus the more indicators that are stacked in your favor the better. Of course as seen the past few weeks, news will trump patterns in the short term.