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It's the effect size, stupid: what effect size is and why it is important

It's the effect size, stupid: what effect size is and why it is important
It's the Effect Size, StupidWhat effect size is and why it is important Robert CoeSchool of Education, University of Durham, email Paper presented at the Annual Conference of the British Educational Research Association, University of Exeter, England, 12-14 September 2002 Abstract Effect size is a simple way of quantifying the difference between two groups that has many advantages over the use of tests of statistical significance alone. 'Effect size' is simply a way of quantifying the size of the difference between two groups. The routine use of effect sizes, however, has generally been limited to meta-analysis - for combining and comparing estimates from different studies - and is all too rare in original reports of educational research (Keselman et al., 1998). The following guide is written for non-statisticians, though inevitably some equations and technical language have been used. 1. (a) (b) Figure 1 2. Equation 1 3. Table I: Interpretations of effect sizes 4. 5. 6. 7. Related:  Action Research

The Cult of Outstanding™: the problem with ‘outstanding’ lessons First of all I need to come clean. Up until pretty recently I was a fully paid up member of the Cult of Outstanding™. Last January I considered myself to be a teacher at the height of my powers. In the spirit of self-congratulation I posted a blog entitled Anatomy of an Outstanding Lesson in which I detailed a lesson which I confidently supposed was the apotheosis of great teaching, and stood back to receive plaudits. And indeed they were forthcoming. And then Cristina Milos got in touch to tell me that there was no such thing as an outstanding lesson. The more I’ve read and the deeper I’ve delved into this, the more convinced I’ve become that in our efforts to cast teachers in the mould supposedly preferred by Ofsted we are unwittingly, but actively, undermining our pupils’ ability to learn. But are they wrong? Now the truly mind-bending bit of all this is that sometimes (often?) Sustained & rapid progress Consistently high expectations Excellent subject knowledge OK, you got me.

Effect size In statistics, an effect size is a measure of the strength of a phenomenon[1] (for example, the change in an outcome after experimental intervention). An effect size calculated from data is a descriptive statistic that conveys the estimated magnitude of a relationship without making any statement about whether the apparent relationship in the data reflects a true relationship in the population. In that way, effect sizes complement inferential statistics such as p-values. The concept of effect size already appears in everyday language. Reporting effect sizes is considered good practice when presenting empirical research findings in many fields.[2][3] The reporting of effect sizes facilitates the interpretation of the substantive, as opposed to the statistical, significance of a research result.[4] Effect sizes are particularly prominent in social and medical research. Overview[edit] Population and sample effect sizes[edit] being the estimate of the parameter Types[edit] Cohen's ƒ2[edit] or is

Classroom observation: it’s harder than you think - CEM Blog - Centre for Evaluation and Monitoring Professor Robert Coe We’ve all done it: observed another teacher’s lesson and made a judgement about how effective the teaching was. Instinctively it feels valid. I am a good teacher; I’ll know a good lesson when I see one. We’ve all experienced it from the other side – being observed – but this time the feeling may be more mixed. In September, I gave a talk at the ResearchED2013 conference. The evidence shows that when untrained observers are asked to judge the quality of a lesson, there is likely to be only modest agreement among them. Research Evidence: Can observers spot good teaching? There are two key issues here. Fortunately, a number of research studies have looked at the reliability of classroom observation ratings. One way to understand these values is to estimate the percentage of judgements that would agree if two raters watch the same lesson. The second key issue is validity: if you get a high rating, does it really mean you are an effective teacher? 1. 2. 3. 4. 5.

Effect Size Calculator What It Does This calculator evaluates the effect size between two means (i.e., Cohen's d; Cohen, 1988), which is the difference between means divided by standard deviation. Between-subjects Studies Enter the two means, plus SDs for each mean. To compute effect size using pooled or control condition SD, only enter one SD (computed as appropriate, of course). Within-subjects Studies For within-subjects studies, one must correct for dependence among means in order to make direct comparisons to effect sizes from between-subjects studies. Calculator for Means and SDs downloadable Excel version Calculation Using t score Alternatively, enter the t score and sample size for each condition. Calculator for t scores and Sample Sizes Choice of SD Term I prefer to use the average of each mean's individual SD, as opposed to pooled or control condition SD. What to Report Report the d value that gets output from this calculator. Why Report Effect Sizes Why Make a Calculator References Cohen, J. (1988). Morris, S.

A Cautionary Tale of Educational Evidence Let me first say that I am a big fan of educational research and undertaking trials in schools. Of course, we are not doctors and surgeons dealing with the clear boundaries of sickness and health, or the obvious dichotomy between medicine and placebo. We can, however, design far more robust trials that help us work out what works best in our classrooms. I think we have a moral imperative to do our best to do so. The pursuit of evidence in education could be better and I’m hopeful we can make this happen. I think that even undertaking the process of controlled trials in the classroom, and attempting to isolate one variable in a fistful of complex variables, has value regardless of the results and we learn much from the process. I have helped design and undertake a small matched trial in our English department last year – see here – and the process and the findings were fascinating. Only this evening I had a cautionary experience with the ‘evidence’. What are we as teachers to think?

tion Research Resources A guide to carrying out and writing an action research report by Vron Leslie, WMCETT ITT Co-ordinator This short guide is written to help you approach the writing of a research report and our best advice is to start thinking about this as soon as you can and planning it into your work/life schedule. The guidelines provide a general introduction to planning and writing a report but it is suggested that you read about writing research reports/dissertations before starting – see bibliography and our resources guide. We hope that you enjoy the experience of carrying out research and remember that your mentor/tutor is there to support you through the process. It might also help you to join a research action set of others writing their reports. The guide can be read here. Below, we have listed some other useful booklets and guides to action research, and right there are links to other types of resources. Guide ‘Action Research: A Guide for Associate Lecturers’ published by the Open University

tion Research in Education Search RESINED Home Beginning Research | Action Research | Case Study | Interviews | Observation Techniques | Education Research in the Postmodern Evaluation Research in Education | Narrative| Presentations | Qualitative Research | Quantitative Methods | Questionnaires | Writing up Research Action Research in Education Currently overseen by Maureen McGinty Originally prepared by Dr Stephen Waters-Adams © S Waters-Adams, Faculty of Education, University of Plymouth, 2006 Part One: Introduction Part Two: A Theoretical Underpinning for Action Research in Education Part Three: Doing Action Research Part Four: Limitations and Criticisms of Action Research Part Five: Tasks Part Six: Further Reading 1 Why should I use action research? Because you want to change your practice. 2 How does this qualify as research? Because the act of finding your solution makes you understand your practice better – not only what you are doing, but also the factors that affect what you do. 3 What do we mean by practice? by using