I have done intraobserver and interobserver reproducibility of a method to determine myocardial strain, as well as comparing that method with an established method. 

I know that my possible sources of variance are the observer, the methods i have used, the intraobserver test, the volunteers whose images i used.

However, i am finding it hard to determine the percentage of variance each contributed to the final variance of myocardial strain . 

it is similar to the attached paper 

Article Interobserver, Intraobserver and Intrapatient Reliability Sc...