Progress in International Reading Literacy Study (pirls)

participated in ePIRLS. In total, 4,425 U.S. students 
participated in PIRLS and 4,090 of these students also 
participated in ePIRLS. 
The U.S. sampling frame was explicitly stratified by three 
categorical variables: Poverty status (high or low, defined 
by percentage of students eligible for free or reduced-price 
lunch); type of school (public or private); and region of the 
country (Northeast, Central, West, Southeast). The U.S. 
sample was implicitly stratified (that is, sorted for sampling) 
by two categorical variables: locality (four levels) and 
minority status (above or below 15 percent of the student 
population). 
PIRLS, page 6 

---

NCES Handbook of Survey Methods 
Implementation 
PIRLS is sponsored by the IEA and carried out under a 
contract with the TIMSS & PIRLS International Study 
Center and the data collection contractor. The National 
Center for Education Statistics, in the Institute of Education 
Sciences at the U.S. Department of Education, is 
responsible for the implementation of PIRLS in the United 
States. PIRLS emphasizes the use of standardized 
procedures in all participating education systems, so that 
each education system collected its own data based on 
comprehensive manuals and training materials. These 
materials explain the
survey’s implementation, including
precise instructions for the work of school coordinators and 
scripts for test administrators to use in testing sessions. The 
International Study Center monitors compliance with the 
standardized procedures. 
The PIRLS 2001 instruments were translated into 35 
languages. The PIRLS 2006 instruments were again 
prepared in English and then translated into 45 languages. 
Although most countries administer the assessment in just 
one language, there have been some exceptions. For 
example, in 2006, nine countries plus the five Canadian 
provinces administered PIRLS in two languages, Spain 
administered the assessment in its five official languages, 
and South Africa administered the assessment in eleven 
languages. To ensure comparability among translated 
instruments, the International Study Center established 
guidelines and reviewed and approved all adaptions. For 
PIRLS 2011, the assessment was translated into 45 different 
languages. 
The PIRLS 2016 assessment instruments were translated 
into 40 different languages, across 50 participating 
countries and 6 benchmarking entities, the PIRLS Literacy 
assessment instruments were translated into 10 languages 
across 6 countries, and the ePIRLS assessment instruments 
were translated into 14 languages across 14 countries and 2 
benchmarking entities. Of these participants, 24 countries 
and 4 benchmarking entities administered the instruments in 
more than one language.