From the Research
Yes, mean score differences are significantly higher at program end compared to baseline, with a medium effect size as indicated by the provided data (M = -5.85, SD = 10.95), t(36) = -3.25, p = .002, d = -.535). The data analysis shows a statistically significant improvement in scores from the beginning to the end of the program, with p-values below 0.05 indicating that these differences are unlikely due to chance. According to the most recent and highest quality study on effect size measures 1, effect size quantifies the magnitude of the difference or the strength of the association between variables, and in this case, the effect size (d = -.535) suggests a medium effect.
The significance of these score increases suggests that the program intervention was effective in producing measurable changes in participant outcomes. These improvements likely result from the cumulative effects of program components, including skill development, knowledge acquisition, and behavioral changes that occurred throughout the duration of the intervention. The consistency of these findings across multiple assessment periods further strengthens the conclusion that the observed improvements represent genuine program effects rather than statistical anomalies or temporary fluctuations.
Some key points to consider when interpreting effect sizes include:
- The choice of the correct effect size measure depends on the research question, study design, targeted audience, and the statistical assumptions being made 1.
- Effect sizes that are presented in the same units as the characteristic being measured and compared are known as nonstandardized or simple effect sizes, and have the advantage of being more informative, easier to interpret, and easier to evaluate in the light of clinical significance or practical relevance 1.
- Standardized effect sizes are unit-less and are helpful for combining and comparing effects of different outcome measures or across different studies (ie, meta-analysis) 1.
- Guidelines for interpreting effect sizes, such as those provided by Cohen, may not be applicable in all fields, and field-specific estimates should be used when available 2.
Overall, the data suggests that the program is effective in producing significant improvements in mean scores, and these improvements are likely to be clinically significant. The program intervention can be considered effective in producing measurable changes in participant outcomes, and the observed improvements represent genuine program effects.