"fairly effective in" is a correct and usable phrase in written English.
You can use it in a sentence when you want to describe something that is moderately successful at doing a certain task. For example: "The new marketing campaign was fairly effective in boosting sales by 10%."
But while particulate traps have been fairly effective in cutting this type of pollution from vehicles, standards to cut NO2 emissions have been a huge failure.
It remains fairly effective in regulating bank lending, thinks Mr Shih, "but there are huge sums of private money sloshing around that Beijing cannot control".
The Austrian view has a hard time explaining how so many investors can be fooled into so much malinvestment, especially given the traditional Austrian perspective that markets are fairly effective in allocating resources.
Since March 2002, 35 NGO staff have been killed.On balance, the PRTs have been a useful improvisation in difficult circumstances, fairly effective in improving security but less so at development work.
Multi-cell thin-walled structures have proven fairly effective in energy absorption and have been extensively used in vehicle engineering.
The vaccine proved fairly effective in preventing illness from three serotypes, cutting infection rates by 55.6% for serotype 1, 75.3% for serotype 3, and 100% for serotype 4 after three injections.
The original campaign was fairly effective, if only temporarily.
Barack Obama has been a fairly effective president in terms of "Dudes in the desert murdered by robot planes," but if you disagree with the robots-killing-people policy (like some dirty peacenik hippie), you won't find much to like about Mitt Romney either, as he thinks the guy who had Osama bin Ladin killed and bombed Libya is a gigantic pussy who "apologizes for America".
A combination of these treatments can be a fairly effective method in its treatment (Smego et al. 2003; Smego and Sebanego 2005; Yagci et al. 2005).
Each citizen and their family receive fairly effective medical care in exchange for less than 10% of their salary.
Ms. Abril, though stuck in the dowdier role, has been compensated with two musical numbers, in which she performs a fairly effective imitation of Rita Hayworth in "Gilda".
