Impact: Earth! written by Gareth Collins , H. Jay Melosh and Robert Marcus
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Focus group discussions were instrumental in developing a 30-minute online survey, which was administered in phase two of the research to a national sample of middle and high school teachers. The survey results reported here are based on a non-probability sample of 2,462 middle and high school teachers currently teaching in the ., Puerto Rico, and the . Virgin Islands. Of these 2,462 teachers, 2,067 completed the entire survey; all percentages reported are based on those answering each question. The sample is not a probability sample of all teachers because it was not practical to assemble a sampling frame of this population. Instead, two large lists of teachers were assembled: one included 42,879 AP teachers who had agreed to allow the College Board to contact them (about one-third of all AP teachers), while the other was a list of 5,869 teachers who participated in the National Writing Project’s Summer Institute during 2007-2011 and who were not already part of the AP sample. A stratified random sample of 16,721 AP teachers was drawn from the AP teacher list, based on subject taught, state, and grade level, while all members of the NWP list were included in the final sample.