IMO the government's incentives are generally better aligned with truth telling but there are reasons[1] that independent studies may still catch the government out.
1. Famously, up here in Canada, Stephen Harper suppressed accurate dissemination of climate data during his administration that was only really discovered through independent analysis.
A company may have accurate information that their product causes cancer, but they aren't going to tell you that. They'll outright lie and say it doesn't, hire scientists to create fake research to "prove" that it's safe, and harass, threaten, and discredit anyone who tries to tell the public the truth.