This Zen task is one of the most difficult to recognize as it widely varies in its structure and can easily be conflated with its opposite task of best example of principle. That part of the principle strand zooms in, whereas the task for today's post zooms out to the general.
The correct answer to a best principle for example question will map onto the evidence presented in the stimulus with all the relevant relationships and degrees intact. Thus, the same strategy of identifying actors, their relationships, and degrees of certainty that works for the extrapolation strand will also apply for this task.
All the free Zen of 180 explanations are for the two sample PrepTests, from June 2007 and October 1996, although the 96 test didn't have any best principle questions. The question stem for this task is very difficult to identify, so be sure to actively read it to determine the relationships you're looking for. Marking the stimulus for actors and relationships with both highlighter and pencil will help you make a clean prephrase of the overarching themes you'll look for in the answer choices.
Above is a gallery of the logical reasoning sections that have a greater than average density of the task, and below is the frequency that this task has been asked on modern LSATs and the percentage change in frequency from pre-2007 LSATs. It averages 4.4% of the points on a modern LSAT, and you can reasonably expect at least two points to be devoted to exclusively finding a principle for an example.
on LSATs since 2007
|4.4% of LR|
(2 per LSAT, range 0-4)
|0.9% growth from pre-2007|
This task has not only become more common on modern LSATs, it has also become slightly more complicated in that the stimulus has a multitude of different question stems that trigger it.