Results – Trends in Reading Acheivement – PIRLS 2021

PIRLS 2021 International Results in Reading

Trends in Reading Achievement


Trends in Average Reading Achievement

Considering the PIRLS 2021 trend measures, it is well established that the COVID-19 pandemic, which happened after the 2016 cycle, made a major difference in school-based learning in many countries between 2016 and 2021. It also is well known that previous trend cycles were not affected by such a pandemic, so to represent this major difference for the most recent cycle in this report, the trends between 2016 and 2021 are shown with dotted lines. The dotted line is meant to call attention to the fact that the worldwide COVID-19 pandemic occurred after 2016, but the annotation does not indicate the size of the impact or even that there definitely was an impact in each country. The considerable variation in the extent and response to the pandemic within and across countries makes it impossible to estimate the magnitude of a COVID-19 effect uniformly across countries or country by country at this time. It is more defensible to use ancillary national, regional, and local data to study the impact of the pandemic on student achievement within a country.

Analyzing trend results requires comparable cycle-to-cycle data of the estimates of average achievement that can be considered persistent rather than being the reflection of a particular circumstance. Country trend graphs are therefore generated only if there are comparable data points from at least one previous cycle and the current cycle. This leads to some attrition in the 57 countries and 8 benchmarking entities that participated in PIRLS 2021. As previously explained, 14 countries and 3 benchmarking entities delayed their PIRLS 2021 data collection so that they did not have comparable data in 2021. Next, 8 of the 43 countries that collected their PIRLS 2021 data at the end of the fourth grade school year had other reasons for not having comparable trend data from at least one previous cycle (e.g., 2021 was their first time participating in PIRLS, there was a major change in population definition, or they made numerous changes in translations of material reserved for trend).

For the 35 countries and three benchmarking entities that met the requirement for comparable trend data across two cycles or more, the results are presented in Exhibits 2.1.1 and 2.1.2. Exhibit 2.1.1 presents graphical representations of the differences in average reading achievement between PIRLS assessments. The data in Exhibit 2.1.2 provides the details documenting the changes in average achievement between specific assessments

Click the ‘View Data Visualization’ button for an interactive version of the trend plots in average reading achievement from Exhibits 2.1 and 2.2, combined.



Because the COVID-19 pandemic could have impacted recent trends between PIRLS 2021 and PIRLS 2016, those trends are discussed first. Of the 32 countries and 1 benchmarking participant with data in both 2016 and 2021, 21 countries (and the 1 benchmarking entity) had lower average reading achievement in 2021 than in 2016, 8 had no or little change, and only 3 had higher average achievement. That two-thirds of the PIRLS 2021 countries had a decline in average reading achievement between 2016 and 2021 suggests at least some widespread negative impact from the pandemic on reading achievement at the fourth grade. Also, looking only at the 21 countries with lower achievement in 2021 compared to 2016, 8 showed an improvement in 2016 compared to 2011 and 3 had no change. That is, in a number of countries an upward or stable trend from 2011 to 2016 changed to a downward trend in 2021.

The prevalence of downward trends in 2021 compared to 2016 also influenced the trends between 2021 and the previous cycles, complicating the picture of long-term trends. Singapore was the only country that showed steady improvement with each of the five PIRLS assessments. Slovenia posted improvements across the first four consecutive assessments until the recent decline in 2021. However, in general, the 15 countries that have comparable data across four or five assessments since 2001 have had their “ups and downs.”

Interestingly, despite the enormous challenge of maintaining educational improvement and the recent COVID-19 global pandemic, comparing just the 20-year trend results from start to finish between 2001 and 2021 for the 18 countries that participated in both assessments, there were 7 increases in average reading achievement, 6 with about the same achievement, and only 5 decreases in achievement. Also, considering this relative stability in achievement over the past 20 years and the enormous growth in the amount and variety of reading materials that today’s fourth grade students encounter in their daily lives due to the internet, perhaps there are some positive notes in the PIRLS 2021 long-term trends. This means that while countries see some changes in their achievement over time on a grand scale, at least for the set of 18 countries from which we have long term data, there is long term stability in achievement over time.

The trend results for the 14 countries that needed to delay the assessment of the fourth grade cohort until the beginning of the fifth grade are shown in Exhibit 2.2.1 (trend plots) and Exhibit 2.2.2 (differences in average achievement between the assessment cycles). The results show that 6 of the 13 countries with data from PIRLS 2016 had higher achievement in 2021 than in 2016. As explained previously (see earlier subsection: Impacts of Modifying the Assessment Schedule on Students’ Achievement), the high level of achievement for these countries in PIRLS 2021 may be partly due to the advantage of collecting data on somewhat older students (half a year older on average). The delay in the assessment for these PIRLS 2021 countries may have increased the size of the gains in achievement to an unknown degree. However, age alone cannot be made responsible or separated out. Precise comparisons cannot be made back to PIRLS 2016, and it is noteworthy that a number of these countries also had high levels of reading achievement in 2016.