Sometimes, it is simply too difficult to give a handy summary of what is happening in schools. I was reminded of this during general election discussions about behaviour in classrooms. Has it really improved? This seems a simple enough question, but it is rather hard to answer.

A first, important, variable is timing. If we want to make a causal claim, then it is hard, maybe impossible, to untangle all the policy changes during the time frame: how do we know it was to do with any one intervention?

The second issue is to do with the data itself. In this case, it may have come from the Organisation for Economic Cooperation and Development’s Programme for International Student Assessment (Pisa) or Teaching and Learning International Survey (Talis), or the International Association for the Evaluation of Educational Achievement’s Trends in International Mathematics and Science Study (Timss). But Pisa, for example, involves 15-year-olds: it would not be sensible to use it for claims about primary education.

A third significant variable is who you ask. Pisa 2018 asked students questions about discipline in their language-of-instruction lessons, which resulted in a scale. Typical high scorers (those with a better disciplinary climate according to that scale) are countries such as Japan and South Korea. Low scorers include Argentina and Brazil. The UK is just above the OECD average. Note, this is about the perception of students not teachers. Also, the scores are relative to other countries, which is useful for country comparisons but problematic for tracking changes over time.

Lastly, what if sources disagree? English principals in Timss for both Year 5 and Year 9 (4th and 8th grade in the language of the study) reported “hardly any problems”, gaining one of the highest scores and improving from 2011-15. Under the measure of a “safe and orderly school”, teachers in 4th grade reported similarly high scores and improvements from 2011-15, but 8th grade teachers were less positive: for this category, England was in the middle of the pack and hadn’t experienced much change.

Which country scored the lowest? Japan, despite having one of the highest scores for disciplinary climate in Pisa 2018.

Talis, which also questioned teachers, did not see much improvement in the behaviour of lower-secondary students from 2013-18. It reported slightly lower self-efficacy scores for maintaining classroom discipline between 2013 and 2018. There was an increase in occurrences of some behavioural issues in English schools during this time.

The bottom line is that we can’t simply say behaviour “has improved” or “become worse”. We will always get a nuanced and diverse picture of a complex phenomenon.

Christian Bokhove is associate professor in maths education at the University of Southampton

This article originally appeared in the 31 January 2020 issue under the headline “Behaviour: has it really improved?”