Why this retracement rather than one of the many others which occurred beforehand? Because we're at the upper limit of the trend channel. Without context, one is just stumbling around in the dark with a penlite.
This is what I struggled with in terms of backtesting. In some respects, backtesting seems a bit "hollow" in that you're just looking at statistical probabilities based on as few variables as possible so as not to over complicate I think. Each time you introduce a new variable, you need to further segment the data.
As I go through my charts and look at retracements, if I filter out which of these are close to hourly or daily support/resistance, and where this occurs in the trend channel, there might perhaps be a way to increase the win rate. But this amount of work would almost be impossible and difficult to track because you'd have to seperate out all the retracements that happen in some context and hence there might be many different "types" of retracements. (ie. RETs close to trend channel extremes.... RETs close to the mean.... RETs close to PDHs and PDLs)
(As an aside, the important RETs that I want to study next after I'm done with 5 min line breaks is RETs after big drops or rises.... but once again, this won't have the context of the day/week built in, just simply the context of a price bar being much larger than the other bars around and hence a quick drop or rise)
Of course as you say though, given context, and knowing the LOLR, this makes trading in that direction that much more likely, and hence makes that retracement that much more likely to produce a very good move. So what I'm left with I think is still that you gotta backtest certain strategies, but always be left thinking a bit in real time and having a feel for when to apply a certain strategy. (ie. perhaps making sure to be selective with whatever longs might set up on a day like today even though an initial line break followed by a RET might occur. Since we never know what will happen, cherry picking trades is dangerous, but if the LOLR is down given the channel top, is it fair to skip some longs that might set up mechanically?)
Are there any glaring errors in this line of thought?