The phrase "a known effect" is correct and usable in written English.
It can be used when referring to an effect that is recognized or established in a particular context, such as scientific research or discussions about phenomena.
Example: "The researchers observed a known effect of temperature on the rate of chemical reactions."
Alternatives: "an established effect" or "a recognized effect."
And flower scents have a known effect on bees: if the insects haven't been foraging for a few days, the scent spurs them to resume, often at a food source they have visited before.
How does a major philanthropic donor, for example, decide between spending $100 million in Africa on bed nets, which have a known effect on the transmission of malaria, or spending the same sum on an unproven vaccine that could either be much more effective than bed nets or be a total failure?
In addition, we included a dummy variable for being the oldest sibling, as birth order has a known effect on health [34].
This clearly has relevance for the use of glass versus resin microspheres, due to differences in specific activity and therefore different sphere density during treatment, which has a known effect on the dose coverage [30].
Vitamin D insufficiency has a known effect on bone density, neonatal vitamin D and calcium status, and childhood rickets [ 9].
Since aging has a known effect on resting and exercising blood flow, the data in figure 3 has been plotted in relationship to age.
Reduction of hip fractures is a well known effect of CEE and, interestingly, we found that ossification was a major significant affected network.
Beating [11] is a well known effect observed from adding two sinusoids with similar frequencies, in which they "melt" into a single tone with additional modulation.
Furthermore, increased production of glutathione, due to induction of glutathione synthetic enzymes is a well known effect of increased expression of the Nrf2/ARE genes.
Promoter autoregulation is a well known effect and has been reported for other proteins before [ 16].
So until there is more definitive evidence, it doesn't seem right to imply that there is a clear and known effect.
