Do certified teachers produce better school results?
The question of teacher certification and school results has a seemingly simple logic: certified teachers should deliver better teaching, which in turn should produce higher merit values. But reality is more complex.
The bubble chart shows a positive relationship — schools with a high share of certified teachers tend to have higher merit values. But the spread is wide. There are schools with 100 % certified teachers and mediocre results, and schools with lower certification but top results.
The explanation is that teacher certification co-varies with other factors. Schools in attractive residential areas find it easier to recruit certified teachers and simultaneously have pupils with favourable socioeconomic backgrounds. That makes it difficult to isolate the effect of certification itself.
Nevertheless, research shows that teacher quality is the single most important factor that schools themselves can influence. The size of the bubbles (pupil count) reveals that it is primarily the very largest schools that consistently have high certification and high results.
Statistics: academic year 2023/24. Source: Skolverket open data, Kolada and SCB. Processed by Skolkoll. Glossary · About the data.