The phrase "a small but consistent" is correct and usable in written English.
It can be used to describe something that is minor in size or amount but steady or reliable over time.
Example: "The project received a small but consistent amount of funding, allowing it to progress steadily."
Alternatives: "a modest yet steady" or "a slight but reliable".
Ken Kaiser, last night's plate umpire, typically calls a small but consistent strike zone.
Democrats have begun to open up a small but consistent lead.
A recent review and meta-analysis27 concludes that TBS over prefrontal areas exerts a small but consistent effect on behavior.
"There are always going to be a small but consistent group of people in our culture who will want to do the maximum damage to other human beings.
Labour has clung to a small but consistent poll lead for months, but in the past couple of weeks even that weak reed has snapped.
In February, March, April, May and June, the survey shows a small but consistent lead for Mr. Romney of between one and three percentage points.
A study following more than 1,800 children from ages 6 months to nearly 8 years old found a small but consistent association between increased television viewing and shorter sleep duration.
The majority of DNA in dental calculus is microbial and originates from the oral microbiome; however, a small but consistent proportion of DNA (mean 0.08 ± 0.08%, range 0.007 0.47%) derives from the host genome.
However, our laboratory measurements showed that N application had no effect on Rh in mineral soil, but a small but consistent increase for 10 weeks when the mineral soil had an LFH (litter-fibric-humus) layer on the surface.
It is also a small but consistent exporter of oil and natural gas.
They reveal a small but consistent difference in difficulty of around 3 raw score points across the middle range of scores.
