Another confounding variable when it comes to determining whether a particular therapy is effective or not is the EFC or Expectation Fulfillment Confounder. Which, along with Confirmation Bias, Placebo, Regression to the Mean and other Confounding Variables, makes it next to impossible to determine whether a particular therapy is working through clinical evidence only.
“But hold on! We have to be careful here. Stability wasn’t measured. Just self reports of stability. And we don’t know what the patients were told. If they patients felt that they were unstable, were told that they scored high on self report measures on instability and then were given an exercise program that they were told addresses motor control deficits that contribute to stability with have an Expectation Fulfillment Confounder (EFC). Its not unusual that this subset would respond better because they have been primed to respond better. – Greg Lehman