The Parent Test

How can you conduct a study/ test when all families are not conducting the same test. There is a huge difference between jump off a high dive with no safety harness vs climbing a rock wall with safety gear. The test has no control to accurately compare. Both tests has a fear of heights but one has to do more with physical ability vs taking a leap of trust. I feel the producers did different test for half the parents because they were afraid to lose ratings then actually conduct a test to compare the different parent techniques. So how can viewers see / difference in talking a kid to jump versus talking a kid to climb a wall?