Helmert Contrast
- Compares mean values across groups to assess whether observed differences reflect real effects or chance.
- Applies when you have two or more groups (for example, treatment versus placebo, or multiple teaching methods).
- Results indicate whether one mean differs from others in a way that reaches statistical significance.
Definition
Section titled “Definition”Helmert contrast is a statistical technique used to compare the means of two or more groups. It is used to determine whether the differences between the means are statistically significant, or if they are due to chance.
Explanation
Section titled “Explanation”Helmert contrast compares group means by evaluating whether observed mean differences are unlikely to have occurred by chance. In practice, researchers compute mean scores for each group on an outcome measure and use Helmert contrast to test whether the differences between those means reach statistical significance. If the difference is statistically significant, this suggests an effect associated with the grouping variable (for example, a treatment or teaching method).
Examples
Section titled “Examples”Depression medication example (two groups)
Section titled “Depression medication example (two groups)”Researchers divide subjects into two groups: one group receives the new medication, while the other group receives a placebo. Helmert contrast is used to compare the mean scores on a depression rating scale for each group. If the difference in mean scores is statistically significant, this suggests that the new medication is effective in treating depression.
Teaching methods example (three groups)
Section titled “Teaching methods example (three groups)”Researchers divide subjects into three groups: one group receives traditional teaching methods, one group receives interactive teaching methods, and one group receives blended teaching methods. Helmert contrast is used to compare the mean scores on a standardized test for each group. If the differences in mean scores are statistically significant, this suggests that one of the teaching methods is more effective than the others.
Use cases
Section titled “Use cases”Helmert contrast can be applied to a wide range of research questions, including studies of the effectiveness of interventions, the effects of different treatments or interventions, and the comparison of different groups or populations.
Related terms
Section titled “Related terms”- Means
- Statistical significance
- Placebo
- Intervention
- Groups / populations