Sampling general education schools
At year 8 level, 120 schools were selected randomly from national lists of state, integrated and private schools teaching at that level, with their probability of selection proportional to the number of students enrolled in the level. The process used ensured that each region was fairly represented. Schools with fewer than four students enrolled at the given level were excluded from these main samples, as were special schools and Mäori immersion schools (such as Kura Kaupapa Mäori).

Sampling Mäori immersion schools
Ten schools were selected randomly from Mäori immersion schools (such as Kura Kaupapa Mäori) that had at least 4 year 8 students, and from other schools that had at least 4 year 8 students in classes classified as Level 1 immersion (80 to 100 percent of instruction taking place in Mäori). Half of the chosen schools were immersion schools and half were general education schools with immersion classes (reflecting the similar numbers of students nationally in the two types of programme).

Pairing small schools
Five of the 120 chosen schools in the general education sample had less than 12 year 8 students. For each of these schools, we identified the nearest small school meeting our criteria to be paired with the first school. Wherever possible, schools with 8 to 11 students were paired with schools with 4 to 7 students, and vice versa. However, the travelling distances between the schools were also taken into account. Three of the 10 schools in the Mäori immersion sample also needed to be paired with other schools of the same type.

Contacting schools
In telephone calls with the principals, we briefly explained the purpose of national monitoring, the safeguards for schools and students, and the practical demands that participation would make on schools and students. We informed the principals about the materials which would be arriving in the school (a copy of a 20 minute NEMP videotape plus copies for all staff and trustees of the general NEMP brochure and the information booklet for sample schools). We asked the principals to consult with their staff and Board of Trustees and confirm their participation. Similar procedures were followed with the principals of the 13 schools in the Mäori immersion sample, but for them brochures in both Mäori and English were sent.

Sampling of students
With their confirmation of participation, each school sent a list of the names of all year 8 students on their roll. Using computer generated random numbers, we randomly selected the required number of students (12, or 4 plus 8 in a pair of small schools), at the same time clustering them into random groups of four students (which would be allocated different sets of assessment tasks). The schools were then sent a list of their selected students and invited to inform us if special care would be needed in assessing any of those students (e.g. students with disabilities or new settlers in New Zealand with very limited skills in English). Where necessary, replacement students were chosen, using the same random sampling procedure. Less than 2 percent of students were replaced for reasons other than moving school or planned absence for the full assessment week.

Communication with parents
Following these discussions with the school, Project staff prepared letters to all of the parents, including a copy of the NEMP brochure, and asked the schools to address the letters and mail them. Parents were told they could obtain further information from Project staff (using an 0800 number) or their school principal, and advised that they had the right to ask that their child be excluded from the assessment. Less than half a percent of the selected students were replaced because they or their parents declined to participate.

Practical arrangement with schools
On the basis of preferences expressed by the schools, we then allocated each school to one of the five assessment weeks available and gave them contact information for the two teachers who would come to the school for a week to conduct the assessments. We also provided information about the assessment schedule and the space and furniture requirements, offering to pay for hire of a nearby facility if the school was too crowded to accommodate the assessment programme.

Resulting samples
For the purposes of this report, we were interested in four groups of year 8 students: