Biotech Values

[p3analyze]

"above statement (and below) literally nullify the overall validity of the observational findings"

Correct. The main bias was due to the fact that those who switched from Lipitor to Simvastatin likely responded poorly to Lipitor, or had poorer prognosis than those who stayed on Lipitor. In other words, a valid statement would be Lipitor doesn't benefit everybody. There is no effective statistical methodology in lieu of a randomized trial to correct this bias.