Effect Sizes & the LEQ |
James Neill |
Notes about LEQ & Effect Sizes
FAQQ: I would like to know few things about LEQ evaluation process. For computing effect sizes (ES) of the LEQ, is it necessary to count standard deviation (SD)? And, if so, are the SDs the constant numbers posted on wilderdom web site or can someone can use it calculating it from SPSS analysis? A: For the Effect Sizes (ES), yes, you need to use a standard deviation (SD). Ideally, the SD used should be the best possible estimate of the SD in the population to which you wish to generalise the results. This means you could either rely on the existing SDs based on ~3000 mostly Australian people aged ~12 to ~60 years (average in the 20's) or use SDs based on existing ADRA data. If you have sufficient LEQ data from your own sample (~say 100+), it probably makes most sense to calculate your own SD. You can calculate SDs by getting descriptive statistics in SPSS. ES calculation does take some extra commands, though e.g. the SPSS syntax on the website. |