Table B-3. Range of item response rates and percentage of items with selected rate ranges by wave and type of weighting: 2007–08 through 2009

Table B-3. Range of item response rates and percentage of items with selected rate ranges by wave and type of weighting: 2007–08 through 2009–10
Wave and type of weighting	Range of item response rate	Percentage of items with a response rate of 85.0 percent or more	Percentage of items with a response rate of 70.0-84.9 percent	Percentage of items with a response rate of less than 70.0 percent
First wave
Base-weighted	0.0-100.0	82.5	10.1	7.4
Final-weighted	0.0-100.0	83.3	8.9	7.8
Second wave without retrospective cases
Base-weighted	4.3-100.0	87.2	8.5	4.3
Final-weighted	3.8-100.0	86.8	8.9	4.3
Second wave with retrospective cases
Base-weighted	4.3-100.0	87.8	7.8	4.4
Final-weighted	3.9-100.0	87.8	7.8	4.4
Third wave
Base-weighted	0.0-100.0	84.3	12.2	3.5
Final-weighted	0.0-100.0	84.7	11.8	3.5
NOTE: Retrospective cases are respondents that were non-interviews during the second wave, but provided replies to second wave items during the third wave. Base-weighted response rates use the inverse of the probability of selection and the sampling adjustment factor. Final-weighted response rates use an initial basic weight, a SASS teacher weighting adjustment factor, a noninterview adjustment factor and a ratio adjustment factor. Detail may not sum to totals because of rounding
SOURCE: U.S. Department of Education, National Center for Education Statistics, Beginning Teacher Longitudinal Study (BTLS), "First Through Third Wave Preliminary Data File, 2007–08, 2008–09, 2009–10".