STATS MAKE ME CRY

Hi,

My graduate studies supervisor has suggested that I read a research paper that conducted a mediation analysis using data from a previous large-scale intervention study (The Causal Role of Phoneme Awareness and Letter-Sound Knowledge in Learning to Read: Combining Intervention Studies with Mediation Analysis, Hulme et al., 2012).

I am not familiar with mediation analysis, so am I correct in understanding that it is a method of determining if factors (in this case phoneme awareness and letter sound knowledge) have a causal role.

The report states, "A mediation model examines how the effects of training on an outcome are transmitted via an intervening (mediating) construct" which I find confusing.

I need a simple explanation of what mediation analysis is, and why it is useful to perform on studies such as the one noted.

Thanks so much!