Final answer:
The most frequently used method of external recruitment for clerical employees is online job portals, where employers post job listings to reach a wide audience.
Step-by-step explanation:
According to studies, the method of external recruitment most frequently used for clerical employees is online job portals. The process of job seeking has significantly changed with the advent of the internet. Now, job seekers can discover job opportunities with ease through various online platforms and social networking sites. Employers utilize these online resources, such as Indeed, LinkedIn, and ZipRecruiter, which pull job listings from different companies, to reach a wider audience of potential employees, making them the most popular strategy for job search. Company websites also often have a Careers section where they post job opportunities, increasing the visibility of these positions to job seekers actively searching on the internet.