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 r.j.coe@dur.ac.uk 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.

Style Anomaly: Value versus Growth - June 23, 2011 This page is temporarily not available. Please check later as it should be available shortly. If you have any questions, please email customer support at support@zacks.com or call 800-767-3771 ext. 9339. Summer is heating up and some of the greatest baseball rivalries are in full swing. One often hears how value stocks outperform growth stocks; hence the value stock anomaly. First, let's define value and growth. To see if a portfolio of high earnings and low price stocks is similar to a portfolio of low estimated growth, I looked at returns to value stocks defined as high E/P and those defined as low EGR. Starting out with a universe of the 3000 most liquid stocks, I tested a value stock portfolio (300 stocks with the highest E/P) and a growth stock portfolio (300 stocks with the lowest E/P) from January 2000 – May 2011. The results over those 11+ years indicate a tendency for value stocks to outperform growth by an average of 1.2% per month for an annualized return of 11.1%.

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.

Strategien SmallCaps - die Börsenfrau® Kleine wachstumsstarke und fundamental gesunde Unternehmen (Small Caps) bieten sich für die Privatanlegerin als Kapitalanlage hervorragend an. Wichtig dabei ist die Auswahl: Folgen Sie einfach den Anlagegrundsätzen der großen Investoren, Benjamin Graham, Warren Buffett und Peter Lynch. Legen Sie Wert auf wachstumsstarke Unternehmen mit erfolgsversprechenden Zukunftsaussichten und soliden Finanzen. Oder schauen Sie sich Unternehmen mit einem bereits etablierten und soliden Geschäftsmodell an, das noch nicht von der breiten Masse des Marktes entdeckt worden ist. Doch lassen Sie "Penny-Stocks" und "Zockerwerte", die nie einen Gewinn erwirtschaftet haben, links liegen. Mit dem Kauf von Aktien erwerben Sie nicht nur ein Stück Papier, sondern einen Anteil an diesem kleinen Unternehmen. Worauf sollten Sie bei kleinen Unternehmen achten? Dazu ist bei einem kleinem Unternehmen vor allem das Wachstum wichtig. Der besondere Charme kleiner Unternehmen »Growth« und »Value« Der Wert- oder Value-Ansatz 1.

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?

Capital Ideas - Rethinking Stock Returns New Evidence on Value Versus Growth Research by Eugene F. Fama "Value Versus Growth: The International Evidence," a 1997 working paper co-written by finance professor Eugene Fama of the University of Chicago Graduate School of Business and Kenneth R. French, a former Chicago faculty member now at the Yale School of Management, argues that the conventional wisdom is wrong. Fama and French define value stocks as those stocks that have high ratios of book value to market value and growth stocks as those that have low ratios of book value to market value. Fama and French reached their findings in the process of examining the validity of the Capital Asset Pricing Model (CAPM) and other asset pricing models. Seeking to test the validity of CAPM, Fama and French in 1992 examined the variables -- price-earnings ratios, firm size, book-to-market equity and leverage -- that research had determined to be related to average returns. Eugene F.