NAEP Technical DocumentationStudent Sample Selection for the 2005 National Science Assessment

There were three types of sessions: science operational, science bridge, and pilot. Student sampling for the NAEP 2005 national science sample was designed to achieve the session probabilities shown in the table below for each study type, which would provide the necessary targets needed for each assessment overall.

The table also presents the target sample sizes for students in schools for each study type and grade. All grade-eligible students in schools were taken if the school's grade-eligible student count was less than or equal to the maximum value, and samples equal to the target were taken for schools with grade-eligible student counts greater than the maximum value.

Probabilities for session assignments, by study type and grade: 2005
Study type and grade	Science operational	Science bridge	Pilot	Target	Maximum
Supplemental science operational only (Alaska)	100.00	†	†	30	33
Science bridge and pilot studies only Grade 4	†	72.73	27.27	44	48
Science bridge and pilot studies only Grade 8	†	70.59	29.41	44	48
Supplemental science operational, science bridge, pilot studies Grade 4	56.00	32.00	12.00	75	82
Supplemental science operational, science bridge, pilot studies Grade 8	53.85	33.33	12.82	78	86
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2005.

Science bridge sessions required specialized procedures. In small schools with limited numbers of grade-eligible students, it was preferred that either there were not any science bridge students sampled, a science bridge sample size that was greater than or equal to 12, or all students sampled as science bridge (if there were fewer than 12 students). Small numbers of students split between science bridge and non-science bridge would have resulted in inefficient operational issues (e.g., the requirement of separate classrooms for limited numbers of students).

Schools were classified into three categories: small, medium, and large. Students were assigned to sessions based on the desired probabilities and the size of the school keeping with the operational issues related to small schools and the science bridge assessment.

The process of student list submission, sampling students from year-round schools, sampling new enrollees, and determining student eligibility and exclusion status was the same as for the NAEP State student sample.

Last updated 20 August 2009 (GF)

Printer-friendly Version