The IEA's Trends in International Mathematics and Science Study (TIMSS) is a series of international assessments of the mathematics and science knowledge of students around the world. The participating students come from a diverse set of educational systems (countries or regional jurisdictions of countries) in terms of economic development, geographical location, and population size. In each of the participating educational systems, a minimum of 4500 to 5000 students are evaluated. For each student, contextual data about the learning conditions in mathematics and science are collected from the participating students, their teachers, their principals, and their parents via separate questionnaires.
TIMSS is one of the studies established by the International Association for the Evaluation of Educational Achievement (IEA) aimed at allowing educational systems to compare students' educational achievement and learn from the experiences of others in designing effective education policy. This study was first conducted in 1995, and has been performed every 4 years thereafter. In most of the cycles the study assesses 4th and 8th grade students. Therefore, some of the participating educational systems have trend data across assessments from 1995 to 2015.
TIMSS was first performed in 1995 as the largest international student assessment study of its time and evaluated students in five grades. In the second cycle (1999) only eighth-grade students were tested. In the next cycles (2003, 2007, 2011 and 2015) both 4th and 8th grade students were assessed. The 2011 cycle was performed in the same year as the IEA's Progress in International Reading Literacy Study (PIRLS), offering a comprehensive assessment of math, science and reading for the countries attended both studies. The sixth cycle was conducted in 2015, and the results were released in 2016; the data set will be published in February 2017. TIMSS 2015 included data collected from parents for the first time. TIMSS Advanced, previously conducted in 1995 and 2008, was also conducted in 2015, and assessed final-year secondary students' achievement in advanced mathematics and physics. Policy-relevant data about curriculum emphasis, technology use, and teacher preparation and training accompanies the TIMSS Advanced results.
Along with the overall students’ achievement data, TIMSS comprehensive assessments include data on student performance in different mathematics and science domains (algebra, geometry, biology, chemistry, etc.) and on performance in the problem solving challenges in each of these contexts. In addition, TIMSS provides contextual data on crucial curricular, instructional, and resource-related factors that can impact the teaching and learning process. These data are gathered using student, teacher, school, and curriculum (National) questionnaires filled out respectively by students, teachers, school principals and National Research Coordinators.
According to the TIMSS 2011 international results in Math “The TIMSS mathematics achievement scales were established in TIMSS 1995 based on the achievement distribution across all participating countries, treating each country equally. At each grade level, the scale center point of 500 was set to correspond to the mean of the overall achievement distribution, and 100 points on the scale was set to correspond to the standard deviation. Achievement data from subsequent TIMSS assessment cycles were linked to these scales so that increases or decreases in average achievement may be monitored across assessments. TIMSS uses the scale center point as a point of reference that remains constant from assessment to assessment”.
Because TIMSS studies are done in four-year cycles, it opens the opportunity for participating counties to use the results between the fourth and the eighth grades to track the changes in achievement and certain background factors from an earlier study. For example, results of the fourth grade in TIMSS 1995 can be compared with the results of the eighth grade in TIMSS 1999 as fourth graders had become eighth graders in the next cycle of study.
The IEA's Data Processing Center has developed an application for working with data from TIMSS and other IEA large-scale assessments called the "IEA International Database (IDB) Analyzer".. This application enables researchers to combine data files and facilitates some types of statistical analysis (such as computing means, percentages, percentiles, correlations, and estimating single level multiple linear regression). The application takes into account the complex sample structure of the databases when calculating the statistics and their standard errors. It also allows researchers to estimate achievement scores and their standard errors .
For an overview of the IEA study results and interpretation of information, the IEA's "Data Visualizer". can come in handy.
In the IEA's TIMSS 1995 study, there were 41 educational systems in five grades (third, fourth, seventh, eighth, and the final year of secondary school). In 1999, TIMSS only focused on the eighth grade in 38 educational systems. There was no study done for the fourth grade in that year. In TIMSS 2003, there were 26 educational systems in the study for the fourth grade and 48 for the eighth grade. In TIMSS 2007, 44 educational systems participated in the fourth grade and 57 educational systems in the eighth grade. TIMSS 2011 had 52 participating educational systems for the fourth grade and 45 for the eighth grade.
In TIMSS 2011, nationally representative samples of students in 63 countries and 14 benchmarking entities participated in the fourth grade assessment, the eighth grade assessment, or both. And in each country, almost 4,000 students from 150–200 schools participated at each grade. In some of the participating educational systems where the assessment was too difficult for fourth and eighth grade students, the assessments were administered to 6th and 9th grade students.
TIMSS project depends on the collaboration of a large number of individuals and organizations around the world including the IEA Data Processing and Research Center, TIMSS & PIRLS International Study Center at Boston College, the IEA Secretariat, Statistics Canada, and Educational Testing Service (ETS). In the United States, TIMSS is conducted by the National Center for Education Statistics of the U.S. Department of Education. Data for US students is further tracked for ethnic and racial groups. TIMSS is mainly funded by the participating countries. Also, US National Center for Education Statistics of the US Department of Education and the World Bank provide major support funding of the studies.
In TIMSS 1995 study, there were 25 participating countries for the fourth grade and 41 counties for the eighth grade. In 1999, TIMSS-R only focused on the eighth grade in 38 countries. There was no study done for the fourth grade in that year. In TIMSS 2003, there were 25 participating countries in the study for the fourth grade and 46 countries for the eighth grade. TIMSS 2007 had 36 participating counties for the fourth grade and 49 counties for the eighth grade. TIMSS 2011 had 52 participating countries for the fourth grade and 45 countries for the eighth grade.
Because TIMSS studies are done in four-year cycle, it opens the opportunity for participating counties to use the results between the fourth and the eight grades to track the changes in achievement and certain background factors from an earlier study. For example, results of the fourth grade in TIMSS 1995 are used to compare with the results of the eighth grade in TIMSS-R 1999 as fourth graders had become eighth graders in the next cycle of study.