PIRLS 2011 Design

  • International large-scale sample survey of student achievement and educational context
  • Monitors trends by reporting results from successive cycles on a common achievement scale
  • Predominantly quantitative, with qualitative information presented in descriptive country chapters in the PIRLS encyclopedia
  • Overall data collection approach
    • Proctored assessment of student achievement
    • Self-administered surveys for students, parents, teachers, and school principals
Target population
  • School children in the participating countries in grades representing 4 years of formal schooling
  • In those countries where fourth-grade students were expected to find the PIRLS assessment too difficult, Grade 6 was the target population.
Sample design
Stratified two-stage cluster sample design

First stage: Sampling schools

  • Probability proportional to the size of the school (PPS)
  • Stratifying schools (optional):
    • According to important (demographic) variables (e.g., region of the country, school type or source of funding or languages of instruction)
    • Two forms possible: explicit or implicit stratification
  • Random-start fixed-interval systematic sampling
  • Schools sampled at the same time for field test and main data collection
  • Sampling of two replacement schools for each school sampled (main data collection only)


Second stage: sampling classes within schools

  • Only after sampled schools agreed to participate in the study
  • One or more intact classes from the target grade of each school, selected using systematic random sampling


General notes

  • School sampling conducted by Statistics Canada, class sampling by participating countries
  • All sampling activities monitored and documented by Statistics Canada and IEA Hamburg staff
  • Most of the countries that participated in TIMSS 2011 at Grade 4 also participated in PIRLS 2011 with the same samples of students
Sample size

Per country

  • School sample: minimum 150–200 schools
  • Student sample: about 4,500 students


In total

Approximately 325,000 students participated in PIRLS 2011, including countries assessing students at more than one grade, benchmarking assessments, and prePIRLS

Data collection techniques and instruments

Student Assessment

  • Written format
  • Reading passages and accompanying questions:
    • Multiple-choice (at least half the number of total points)
    • Constructed-response
  • Achievement items
    • 10 item blocks for PIRLS and 8 item blocks for prePIRLS
      • 12–17 items per block
    • 13 test booklets for PIRLS and 9 booklets for prePIRLS
      • Items per assessment
        • PIRLS: 135 items
        • prePIRLS: 123 items
    • Linking mechanisms between booklets and between cycles
      • New passages and items in 2011: 4 blocks
      • The other 6 blocks are trend passages and items (unreleased) from PIRLS 2001 and 2006
  • Matrix sampling of passages/items (rotated test booklet design)


Background questionnaires

  • Student questionnaire, in print format; modular design
  • Learning to Read survey (home questionnaire), to be completed by students’ parents or primary caregivers, in print format
  • Teacher questionnaire, to be completed by the reading teachers of assessed classes, print or online; modular design
  • School questionnaire, to be completed by the principal of each school sampled, in print or online format


Curriculum questionnaire

  • To be completed by NRCs
  • Modular design
  • Online format


Descriptive encyclopedia chapters

  • One chapter for each participating entity
  • Written by experts from ministries of education, research institutes, or institutions of higher education (in countries and benchmarking entities) based on an internationally agreed-upon outline.
  • achievement test
  • questionnaire
  • Assessment instruments administered in 48 languages.
  • Instruments (assessments of achievement and student questionnaires) administered in two or more languages in 17 countries.
  • The most common languages: English (16 countries) and Arabic (7 countries)
Translation procedures
  • International version of all assessment instruments developed in English by TIMSS & PIRLS International Study Center.
  • Instruments then translated and adapted by participating countries into their languages of instruction.
  • Translations verified by independent linguistic and assessment experts in order to ensure equivalence with the international version.
Quality control of operations

During data collection

  • National Research Coordinator (NRC) in each participating country responsible for data collection
  • Standardized survey operations procedures: step-by-step documentation of all operational activities provided with manuals
  • Full-scale field test of all instruments and operational procedures (in each participating country and benchmarking entity)
  • Provision of software tools for supporting activities (e.g., sampling and tracking classes and students, administering school and teacher questionnaires, documenting scoring reliability, creating and checking data files)
  • Training of NRCs and their staff, school coordinators, test administrators, etc.
  • School visits conducted by international quality control monitors (IQCMs) during test administration (15 schools per country)
  • National quality control program
  • Survey activities questionnaire (SAQ) to be completed by NRCs


During data processing and cleaning

  • Testing of all data cleaning programs with simulated data sets
  • Material receipt database
  • National adaptation database
  • Standardized cleaning process
  • Repetition of data cleaning and comparison of new data sets with preceding versions
  • Identification of irregularities in data patterns and correction of data errors