Johnson

You studied for weeks. You know the material cold. Then the exam lands on your desk and your mind goes completely blank. If this sounds familiar, you are far from alone. Research published by the National Institutes of Health shows that between 25 and 40 percent of students experience significant test anxiety, and for some, … Read more

If you have ever run a student feedback survey and wondered whether the results actually represent your school, you are already thinking about nonresponse bias. Learning how to reduce nonresponse bias in educational surveys is one of the most practical skills a researcher, administrator, or instructor can develop. When the students or teachers who skip … Read more

Every teacher who has handed back a test knows the question that follows: “Can I retake this?” The answer you give shapes how students learn, how parents react, and how much grading work you take home on Friday night. If you have ever wondered how to build a fair makeup and retake assessment policy that … Read more

Here is the truth most survey guides bury in paragraph six: the response rate percentage is not what makes a survey valid. What matters is whether you collected enough absolute responses to draw conclusions within an acceptable margin of error. A 5% response rate from a population of 100,000 gives you 5,000 responses, which is … Read more

You ran your reliability analysis and now you are staring at a number between 0 and 1. Whether you are writing a thesis, polishing a journal manuscript, or validating a questionnaire for the first time, you need to know what that number actually tells you about your scale. Learning how to interpret a Cronbach’s alpha … Read more

Cronbach’s alpha is a reliability coefficient that measures the internal consistency of a set of items in a survey, questionnaire, or psychological scale. It ranges from 0 to 1, with higher values indicating greater reliability among the items. When you submit a research paper, thesis, or dissertation, every statistical value must follow the formatting rules … Read more

If you are validating a questionnaire or scale, you need a reliability coefficient that holds up under real-world conditions. Cronbach’s alpha has been the default choice for decades, but McDonald’s omega is increasingly recommended by psychometricians as the more accurate alternative. The good news is that calculating McDonald’s omega in jamovi takes only a few … Read more

Cohen’s kappa (kappa) is a chance-corrected statistic that measures the level of agreement between two raters who classify items into the same categorical groups. It ranges from -1 (complete disagreement) to +1 (perfect agreement), with 0 indicating no agreement beyond what random chance would produce. Unlike simple percent agreement, Cohen’s kappa accounts for the fact … Read more

If you have ever tried to measure how reliably two people agree when rating something, you have probably run into Cohen’s kappa. It is one of the most widely used agreement coefficients in statistics, research, and machine learning. But the moment your categories have a natural order, like a Likert scale from “strongly disagree” to … Read more

If you are working on a study that involves multiple raters scoring the same subjects, you have probably run into the intraclass correlation coefficient (ICC). Learning how to interpret the intraclass correlation coefficient for rater agreement is one of the most useful skills you can build as a researcher, clinician, or data analyst, because it … Read more