Case-Control Study Design

FYI:
1. Here is what we shall discuss (I prophesy:)
2. Then something pertaining to this
3. But ultimately, it will all be about this!

So I argue each of the FYI points in detail (and English) presently:
1. you have two-population-in-one (study population = cases + controls) and what really interests you is the difference (conceptually, statistically & literally) between the two
2. if 1,000 studies like yours (hypothesis, sample size, etc.) are done, each study will estimate the difference, in odds of exposure, between cases & controls and report this as a t-statistic. 1,000 such statistics will follow the distribution outline in the picture (either the red or the green one; we don't know!!!). Your study (which is all we know!!!) will also estimate the difference in odds of exposure between cases & controls & result in the blue vertical line in the picture :) Of course the question becomes a HAMLET style question from this point: "To Blue or To Green, That is the Question!" Red, with a log(odds) difference = 0 is obviously the null distribution. We can easily perceive that larger sample sizes make our lives easier & reduce our risks of making wrong inferences (type I or type II errors:)
3. So #1 deals with an idea (concept). #2 then translates this concept into statistics so that it can be tested in the REAL WORLD which occurs, not as ideas, but as measurable stuff! #3, however, is the biological argument & reasoning. the link i posted takes you to a nutshell LITERALLY. In this case, specifically, it takes you to the bottom left item = DNA. Feel free to click on it & see where it takes you!!! This is where you'd realize that "lagging" your exposure variable is essential.


See an example of a study in which lagging was used analytically:

Mortality from brain cancer was modestly increased among men with < 2000 hours (RR 1.61, 95% CI 0.86 to 3.01) and > 2000-10,000 hours exposure (RR 1.79, 95% CI 0.81 to 3.95), but there were no deaths from brain cancer among the most highly exposed men. A lag of five years yielded slightly increased RRs. Mortality from liver cancer was not associated with exposure to PCB insulating fluids.