A second limitation was the loss of nearly 40 % of the weight and height data at age 4 years, which could have
introduced selection bias.
But
that introduces selection bias, small sample size, and it's hard to know if lawyers are reporting accurately.
Not exact matches
Before discussing
selection that would
bias assessments of special language program performance downward, I will address two factors that could
introduce upward
biases.
As discussed above, these variables are used to account for the potential
selection bias introduced because of the differences between the populations at choice schools compared to traditional public schools.
This scale factor defines the
bias introduced by a particular
selection of ocean cores, failure of that distribution to represent a true global average, and various assumptions in converting the proxy data into a temperature change.
Although randomization design reduces
selection bias, it
introduces possible spillover effects.
Second, the attrition rates in this study were substantial, which of course
introduces the possibility of a
selection bias.