The phrase "an external expert" is correct and usable in written English.
You can use it when referring to a specialist or consultant who is not part of the organization but is brought in for their expertise.
Example: "To ensure the success of the project, we decided to consult an external expert in environmental science."
Alternatives: "an outside consultant" or "a third-party specialist."
It's best if done by the employees' supervisor or an external expert (not an H.R. official with no direct oversight).
Should the board have a cyber-expert director or should the board bring in an external expert?
A local service technician can be supervised remotely by an external expert in the context of telemaintenance.
A draft report was released Friday for public comment and peer review, in advance of an external expert review from March 26 to 28.
Over the following months, an external expert group, which included representatives from non-governmental organizations, reviewed and provided final feedback on the glossary.
She has served as an external expert for the World Health Organization Nutrition Guidelines Group, Chair of the B-vitamins and One-Carbon Metabolism symposium at the Experimental Biology conference, expert consultant for the World Health Organization, and NIH reviewer for the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
We also provided further supporting evidence for GAP's predictions from an external expert-curated gene-disease association database.
Developed with active participation from patients, researchers, and the PCORI staff (as an external experts' advisory group that did not participate in conducting this SR), this systematic review takes priority in establishing the baseline starting point from which we need to advance the science of patient engagement in research.
They had not been involved in the ART treatments and had been trained over four days in a course delivered by an external international expert.
All samples with a primary histology result of CIN2+ were reviewed by an independent external expert.
Also, continuing to contribute to fusion energy diagnostics development and working as an F4E external expert for ITER International Thermonuclear Experimental Reactorr).
