The phrase "small decrease" means that there is a small reduction or lessening of something, usually indicating a slight decline or decrease in value, quantity, or size. Full definition
The models show less agreement regarding summer precipitation patterns, though a slight majority of models suggest that there may be very small decreases in summer precipitation, particularly in the southeast. (montanaclimate.org)
Even small decreases in your discretionary spending will allow you to increase your vacation savings. (synchronybank.com)
If those could be treated by c - section then again there would be a situation of lots of c - sections in exchange for a vary small decrease in maternal death. (skepticalob.com)