First, we limited the analysis to members with at least two baseline years of data to better control for possible

regression to the mean effects.

The identification of a similar comparison group limits the threats of history, maturation, and

regression to the mean that are common to observational studies lacking such a comparison.

The second internal validity concern is

regression to the mean.

This finding suggests that the observed improvement on the competencies selected for development was significantly greater than explained by

regression to the mean.

Changes in biochemical markers of bone turnover in women treated with raloxifene: influence of

regression to the mean.

Even so, it seems unlikely that

regression to the mean is the entire story, even in reading.

If it is less than one, we have

regression to the mean across generations, a necessary, but not sufficient, condition for inequality (measured by the variance of In y) to decline over time.

And as Bellos put it: "A best-ever result is comparable to an extreme event, and

regression to the mean says that after an extreme event the likelihood is of one less extreme.

The two central issues he focused on were the potential bias introduced by

regression to the mean and the confounding effects of stigma, or the "scarlet letter" (Carnoy 2001: 22) of receiving failing grades from the state.

September 10: Modeling and simulation to adjust p-values in presence of a

regression to the mean effect.

The same reasoning applies to the threat of bias because of history,

regression to the mean, or external environmental influences.

Ornish admitted that there was some

regression to the mean but added, "there is a direct correlation between degree of adherence and outcomes at 1 year.

Krueger and Funder hold that the results are undermined by a statistical effect known as

regression to the mean.

Observed crash data are subject to

regression to the mean, because high short-term crash frequencies are likely to decrease and low short-term crash frequencies are likely to increase as a matter of course, even if no improvements are made.

The study, believed to be the first of its kind in the industry, used statistically sound methodology that eliminates aberrations such as selection bias,

regression to the mean and demographic differences.