The demand was created, first of all, by law — laws that required, for example, testing for syphilis before marriage, testing for syphilis before induction into the army.
Numerical tests involve for example testing for covariate-by-time interactions or for the presence of a trend in the residuals of the model.
I think it's important to assess this by at least one other means; for example, testing whether various HSPs are induced (either individual HSPs or, preferably, a genome-wide transcriptional analysis by arrays or RNA-Seq).
Most contemporary studies of cable news, for example, test their effects by exposing individuals to Fox News Channel or MSNBC and look for similar effects on their subjects' political views.
Others have been hampered by inadequate test performance characteristics (for example, typhoid rapid antibody tests 11) or prohibitive cost (for example, tests detecting urine pneumococcal antigen 12).
Facebook was able to test the effect of introducing the "Like" button, for example, by testing it on large subsets of users.
Although the IV assumptions can never be fully tested empirically, they can be assessed to some extent, for example by testing the association of the genetic variants with measured covariates to assess potential pleiotropy.
For example, by testing antibody stained cells by flow cytometry, an international consortium recently documented somatic WASP alleles, either reversions or second site mutations, in 11% of 272 WAS patients [29].
Yet, few studies have explicitly focused on comparing the test-theoretical properties of the self-report and parent-report versions [ 13], for example by testing for statistically significant differences in Cronbach's alpha coefficients or validity coefficients, even though this is an important question to study.
There are even efforts to use the model for what Ramaswamy calls "ecosystem services" — for example, by testing the effects of climate change on ocean-nutrient flows and phytoplankton to understand the future of fisheries dependent on these microscopic organisms.
