Have to take three CLEP exams within 10 days. I'm overwhelmed!

[sanantone]

Self-selection merely makes it more difficult to ascertain the causation of something, but it can at least help identify a correlation which is still very useful. We can compare different InstantCert subjects, for example, and track them to see trends. For instance, some of the IC subjects are tracking and passing at clearly lower percentages and that correlates with the overall total population rates for those subjects.

Sure, self-selected samples are not scientifically cogent or precise, but they provide something to base inferences from and worth examining. It's not an exact science, and there's a certain level of "gut instinct" and intuition you have to rely on. It's not perfect, but it's better than nothing and gives a good idea.

When looking at all the FY 14 CLEP Civilian Pass rates, essentially every exam with the lowest % pass rates tend to track with the instantcert ones that also are lower than typically seen. For example, CLEP College Algebra is at 59% population rate, and tracks with instantcert's college algebra rates which is at 82% - both of which are lower than usual. DSST Money and Banking is another one which has a 55% official pass rate, and is also much lower on instantcert as well .

We can infer that DSST & CLEP exams for instance that have lower pass rates are going to have lower pass rates on InstantCert as well and that is indeed the case. So yes there is bias involved, but the inferences derived from both sets of data, and student feedback are certainly better than nothing at all. We can certainly extrapolate with some level of awareness, that InstantCert has a tangible effect on markedly improving scores.

I would hypothesize it's simply because people that are using IC materials are more likely to become prepared. I'd also predict that enough people are reporting that they're either passing or failing to at least fathom some questions and identify a correlation with population pass rates. We cannot ascertain precisely what percentage of IC test-takers are passing and failing unless everyone was required to report, but I'd wager that most people would find the information useful for their own purposes. At least the data correlates with the official rates, and the pass rates tend to be higher, which one could infer is due to IC preparing them well. One could easily test that and see if the results are statistically significant i.e. one group that uses IC vs another that uses nothing vs another that uses a textbook and see how each one fares. It would be kind of tedious and an exercise in futility however since most people already assume/believe that test prep is superior in general.

No, it can't even be used for correlation. It could be that 2,000 people took a particular CLEP and of the half who didn't report, most of them failed. That would drastically change the pass rate. Yes, there is some correlation between the IC scores and official CLEP scores only in the assumed relative difficulty of individual tests in comparison to others, but a 90% pass rate makes an exam look extremely easy whereas a 60% pass rate would indicate some significant studying might be needed. The point I'm trying to get across is that you might be able to tell one exam is easier than another, but that still doesn't tell you how difficult that one exam is.

As far as being more prepared, that may or may not be true. We don't know how many people quit IC to turn to another study source. That, again, introduces self-selection bias because the only people using the flashcards are the people who like to study with flashcards. But, all of this really doesn't help the OP, and we're taking the thread off topic.