These studies are often conducted by the AI companies them selves (in this case, an institute that receives funding from AI companies), if they were interested in the truth (which they obviously are not) and not propaganda (which they obviously are) they would fund the necessary research. AI companies have plenty of money and can well afford to do this properly.

Other then AI companies, a more realistic option are state funded universities (particularly in Europe and east Asia) which have consumer protection agencies who’s purpose is to protect their residents from corporate greed, and as such should fund, commission, or even conduct such studies. They also have enough money to do this properly.

If there is enough money for propaganda, there should also be enough money for the truth.