The null hypothesis is one of the most important tools in a researcher’s toolbox. This applies not only to education but to other disciplines as well, particularly with regards to experimental studies. The online library from the University of Southern California describes the null hypothesis as follows with respect to research in education:

“the proposition, to be tested statistically, that the experimental intervention has “no effect,” meaning that the treatment and control groups will not differ as a result of the intervention.”¹

This definition helpfully illustrates the fact that any null hypothesis is statistical in nature, and thus very different from the general public’s understanding of a hypothesis, that is,”an idea that attempts  to explain something but has not yet been tested or proved to be correct”². In fact, since “null” can be understood to mean zero, the null hypothesis is the opposite of whatever hypothesis a researcher is seeking to test. For example, a teacher may believe that that allowing students whose proficiency is low in the language of instruction to use their native language for planning activities would increase their chances of completing the activity successfully. In planning an experiment to test this belief, the teacher would pose a research question, such as

“How does the use of learners’ L1 (native language) impact their performance in skits in an English conversation class for Taiwanese college students?”

Although the teacher in confident the L1 will have an impact given that all the students are native speakers of Mandarin, he poses the null hypothesis since he does not have clear evidence to the contrary:

The use of the learners’ L1 in planning skits has no significant impact on their performance doing role plays in an English conversation class for Taiwanese college students.”

To provide a means of comparison for assessing performance, the teacher will first have students plan skits in groups in groups in which no Mandarin is permitted during the planning stage. This can be done for two different skits in order to ensure the students understand the task. The second set of skits is video recorded for both pedagogical and research purposes. For the following two skit activities, Mandarin is permitted during the planning stage, and the second set of Mandarin-planned skits is recorded. Students are given a questionnaire, bilingually or in Mandarin, seeking their opinion of the skit tasks. For pedagogical purposes, the teacher can, in a subsequent class, show both sets of recordings to the students to show them how much they have improved. At this point, no formal data analysis of the recordings is carried out. Once the course is completed, however, and grades (if applicable) are submitted, the teacher is free conduct formal analysis of the recordings. At this point, however, consent is required from the learners for their recordings to be used for formal analysis. Only recordings for which permission is granted may be used for analysis. The transcripts are analyzed in order to compare the number of idea units in the English-planned and Mandarin-planned skits. Based on the results of the data analysis, the null hypothesis is either supported or rejected. Only if there is a statistically significant difference in the number of idea units between the English-planned and Mandarin-planned skits can the null hypothesis be rejected and only for this particular study.

A teacher’s educated hunches about what can work in the classroom are important and informative. By formulating a research question and testing a null hypothesis based on that question, teachers can formally test their hunches with professional objectivity that fosters their professional development and gives weight to their perspectives in the professional community.

¹Glossary of Research terms, accessed July 31, 2021

https://libguides.usc.edu/writingguide/researchglossary

²MacMillan Dictionary, accessed July 31, 2021

https://www.macmillandictionary.com/dictionary/american/hypothesis#hypothesis_6