The phrase "a research gap" is correct and usable in written English.
You can use this phrase when there is a gap in research on a particular topic. For example, "Recent research has uncovered new information about the evolution of dinosaurs, but there is still a research gap on what occurred after the extinction event."
This paper fills a research gap, outlined by several researchers in the senior consumer field, by identifying the age-related mechanisms that may transform seniors' decision-making behaviors when dining out at a restaurant.
Because of existing a research gap and of course suggestion of previous researchers, in this study, it is tried to regard tactical decisions during the making of strategic decisions.
However, there is a research gap regarding surveys and the digital documentation of Chinese classical gardens.
But there is a research gap in evaluating the performance of project risk management system.
There is a research gap in standardized methods to assess the exposure to airborne nanoparticles in different environments.
There is a research gap regarding the assessment of remanufacturing operational excellence as far as sustainability issues are concerned.
Some target-based decision-making methods have recently been developed; however, a research gap exists in the area.
With such a research gap in existing literature, in these early stages many key façade attributes may be overlooked.
Doing so helps fill a research gap on the literature and build a better understanding of the controversy around the STL trial of Al-Jadeed.
It bridges a research gap by investigating the learning effectiveness of motivational design in M-IBL in a formal English as a Foreign Language (EFL) /L2 educational context.
Although considering risks for gas turbine blade material selection problem or similar high-tech practical cases is important, a research gap exists in such fields.
