Using a screen or SCROG – re-revisited

An acquaintance of mine did a sort of scientific experiment. He used the same light but different plants and a different area to compare the SCROG method with a traditional grow method where plants are not tied down.
First, he grew using the SCROG method, where he grew multiple plants in 1-2 gallon pots under a 400W HPS. We wanted to test how well the plants would grow in a small space.  He kept the plants at three feet (The wire was 2 feet 8 inches off the floor) with the HPS two feet above the tops. This was a little close as some plants showed signs of heat stress.  (I'd recomed an LED next time) He grew the same variety of plants but grew less plants in larger containers (all in 2 gallon pots). The reasoning for the difference was that he figured with the SCROG method, it would be better to have more plants; with more plant tops to tie onto the fence (He also prefers fencing with 2x3 inch holes vs. chicken wire). He said his yield was greater with fewer big plants that were allowed to grow without being tied down. As I said, this is not a real scientific experiment, because he used different containers. You want only one factor or variable to be different when comparing groups. So, in this case we cannot say for sure if the increased yield was due to larger plants/pots or to not being restrained and tied to a screen. I thought some of you might like to atleast have this information.
As always if anyone has any information or further questions please contact me via E-mail

Good Growing,
Dr. E. R. Myers