"slightly prefer" is grammatically correct and can be used in written English.
It means to have a small or subtle preference for something over another. Example: "I slightly prefer tea over coffee in the morning, but I'm not opposed to having a cup of coffee once in a while."
Patient preference assessment; Definitely prefer study drug over prior treatment = 1, Slightly prefer study drug = 2, No preference = 3, Slightly prefer prior treatment = 4, Definitely prefer prior treatment = 5.
bDefinitely prefer study drug over prior treatment = 1, Slightly prefer study drug = 2, No preference = 3, Slightly prefer prior treatment = 4, Definitely prefer prior treatment = 5.
They are very similar, but I slightly prefer the earlier one.
"Merrily" may be my desert-island Sondheim score, and I slightly prefer the original version.
I slightly prefer the 2010 whites, though there are plenty of good 2009s, too.
(I actually slightly prefer the interface on Android, even if my Android camera is not quite as good).
The scenes created without fractal structure were slightly preferred over the scenes with fractal structure (standardize mean contrast=0.138).
I've always slightly preferred Spade to Marlowe, probably just because I thought Hammett was cooler than Chandler.
Nasrallah is said to favour loosening Hezbollah's ties with Tehran slightly, preferring a "Lebanon first" approach that would put party's political programme above its military aims.
Nalbandian slightly preferred to attack Nieminen's backhand, going there 52 percent of the time, but there was no obvious building of the point to open up a weakness.
The result is that we are no closer to knowing which search engine generates the most favoured results, though early indications suggest while Google may be slightly preferred, its margin of success is less than its market share.
