Preliminary analysis from forward simulation indeed suggests that dadi is biased in the direction of estimating bottlenecks of increased severity and duration, as the fraction of positively selected loci increases.
Additive, dominant, and recessive models for each SNP were coded using the major allele (defined in CARE) as the reference allele so that the direction of estimated parameters would be consistently measured across all three studies.
As stated earlier, the opposite direction of estimated effects between the two sunlight surrogates is expected, thus the consistency between our sunlight measures adds strength to our findings despite some of the estimates occurring opposite of the hypothesised direction.
This sensitivity analysis did not change the direction of estimates reported in Table 3; however, the interaction term in model 6 was statistically significant under this restriction.
First, collinearity between the repeated of measures of phthalate metabolites may be an issue because it may lead to inflated standard errors and plausibly change the direction of estimates of β j s [ 13].
It is generally not possible to predict differences in the size, or even the direction, of estimates of treatment effects for the same intervention when it is generated in randomized and non-randomized studies [ 22].
Nevertheless, it is not known to what extent the particularly low rates of C/S in this population together with the differential non-participation rate observed in this study (with higher loss to follow up amongst the subjects of the atopic background group) may have possibly affected the direction of estimates.
Bai et al.[10] worked in this direction and estimated the rate of convergence for the several operators.
In this paper the problem of estimating the direction of arrival (DOA) of the sources in the presence of spatially correlated noise is studied.
Inconsistency, or large variability in the magnitude or direction of estimates of effect across studies that cannot be explained, reduces confidence in the body of evidence.
