In North America at least, biomedical research labs operate largely as fiefdoms of the individual principal investigators (PIs). The actual research work falls almost entirely on the backs of grad students and postdoctoral fellows. The grad students need to generate "good" data in order to graduate, the postdocs need the same in order to gain real employment (with only about 10% gaining faculty positions themselves after many years of postdoctoral training). The PIs need such "productivity" from their trainees in order to gain the funding that keeps the labs going. The PIs themselves face success rates in grant applications that are often 10% or lower and, particularly early in their careers, their job security depends almost entirely on their ability to secure grant funding.
These competitive pressures create enormous incentives for otherwise conscientious people, all the way along the hierarchy described above, to fudge their research data. Research fraud is thus a direct outcome of a fundamentally-broken approach to the structure of research funding.
There are exceptions to that approach, however. The not-for-profit Howard Hughes Research Institute [1], and to an extent the intramural research programs of the NIH [2], offer funding for PIs to do what they do best, without the pressure of competing for scant funds. Coincidentally, some of the best science comes out of these sites.
1: https://www.hhmi.org/scientists 2: https://irp.nih.gov/about-us/what-is-the-irp