TIMSS 2015 Design
Methodology
- International large-scale sample survey of student achievement and educational context
- Monitoring of trends by reporting results from successive cycles on a common achievement scale
- Predominantly quantitative, with qualitative information presented in descriptive country chapters in the TIMSS encyclopedia
Method(s)
- Overall data collection approach:
- Proctored assessment of student achievement
- Self-administered surveys for students, parents, teachers, and school principals
Target population
- School children in grades representing 4 and 8 years of formal schooling in the participating countries
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, level of urbanization)
- Can take two forms: 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 have 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
Sample size
Per country and target grade
- School sample: minimum 150–200 schools
- Student sample: about 4,500 students
In total
Approximately 300,000 students per grade
Data collection techniques and instruments
Student assessments in mathematics and science
- Written format
- Two types of questions
- Multiple-choice (at least half of the total number of points)
- Constructed-response
- Achievement items
- A total of 28 item blocks per grade (14 with mathematics items, 14 with science)
- Items per block
- Grade 4: 10–14 items in each block
- Grade 8: 12–18 items in each block
- Items per block
- A total of 14 test booklets per grade – 4 blocks (2 mathematics, 2 science, in counterbalanced order) per booklet
- Items per assessment
- Grade 4: approx. 170 items in each of mathematics and science
- Grade 8: approx. 200 items in each of mathematics and science
- Items per assessment
- Linking mechanisms between booklets and between cycles
- New items in 2015: 12 blocks (6 mathematics and 6 science)
- The other 8 blocks (for each subject) are trend items (unreleased items) from TIMSS 2011 and 2007.
- A total of 28 item blocks per grade (14 with mathematics items, 14 with science)
- Matrix sampling of items (rotated test booklet design)
Background questionnaires
- Student questionnaire in print format modular design in Grade 4
- Teacher questionnaire to be completed by the mathematics and science teachers of assessed classes, print or online; modular design in Grade 4
- School questionnaire to be completed by the principal of each school sampled in print or online format
- Home questionnaire to be completed by students’ parents or guardians in print or online format
Curriculum questionnaires
- To be completed by NRCs in each participating entity
- 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
Techniques
- achievement or student test
- questionnaire
Languages
- Assessment instruments administered in 43 languages
- Instruments (assessments of achievement and student questionnaires) administered in two or more languages in 22 countries and five benchmarking entities
- The most common languages: English (21 countries), Arabic (10 countries)
Translation procedures
- International version of all assessment instruments developed in English by TIMSS & PIRLS International Study Center.
- Instruments then translated 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 grade and 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
- Standardized cleaning process
- National adaptation database
- Repetition of data cleaning and comparison of new data sets with preceding versions
- Identification of irregularities in data patterns and correction of data errors
Sources - Technical documentation
Other sources