How prevalent is contextual information in research on school bullying?

Empirical articles on school bullying need to give contextual details of the study, including on participants (number, age, gender), the country in which data was gathered, and the year in which it was gathered. We argue that these are important aspects of information, and that country and year of data collection cannot be inferred unambiguously unless they are explicitly stated. We report an analysis of contextual information on a sample of 201 articles, from 1976 to 2015, on school bullying. The great majority of studies gave information on number and age of participants, and most on gender balance. Most also gave explicit information on the country in which data was gathered. However only about one quarter of articles gave information on the date (year) in which data was gathered. For those that did, the average gap from data gathering to publication was 4 years, with a range of 1 to 11 years. We argue that the date of data collection is an important historical aspect, as many societal changes, even over a period of a few years, can impact on prevalence and nature of bullying. We recommend that besides participant and country information, year of data collection is routinely given in empirical articles on school bullying.