I haven't written up an experiment since O-Level Physics. As I recall, the correct layout goes something like this.

Hypothesis: That, since all cleaning products are essentially identical, being designed to interact with cack and water so as to form a rinsable slick or sludge, it should be possible to replace expensive types of cleaning products with cheaper ones.

Prediction: When washed in alternative cleaning products, hair will become clean.

Equipment: One shower, some dirty hair, some washing up liquid, clothes detergent and kitchen cleaner, no shampoo.

Method: Whilst showering, I washed my hair in the above products.

Results: The results were unsatisfactory from a personal grooming point of view.

Conclusion: All cleaning products are not in fact essentially identical.

So now you know. It's not the Schmidt Sting Pain Index, but in some small way I've been there for you.