Sampling methods

The data for this book come from a survey of high school biology teachers conducted between March 5, 2007 and May 1, 2007. More precisely, the data are from two simultaneous studies using identical questionnaires and overlapping sampling frames.

One study was a mail-only study with teachers selected randomly from a database maintained by Quality Education Data. The database contains names and school mailing addresses for more than 80% of public school teachers in the United States. To be eligible for selection, teachers needed to be in a public school that included grades 9 and 10. Each teacher had from one to six job descriptors in the database; to be eligible for selection, at least one descriptor has to be “biology,” “life sciences,” or “AP biology.” This meant that a small number of teachers in our sample identified their primary job function as outside of biology, about 2% identified their primary field as in another science or in science support (e.g., computer lab coordinator), and 12% identified themselves as chair of their high school's science department. Those teachers recruited to teach biology from nonscientific fields were, therefore, eligible for inclusion but comprise a trivial proportion of the sample.