Which of the following factors might be less affected by changes in compensation during recruitment?

The source of hire refers to where applicants come from, such as job boards, referrals, or recruitment agencies. While compensation can influence candidates' decisions to apply or accept an offer, the effectiveness of a source of hire may not change considerably with alterations in compensation levels. For example, if a company typically attracts talent from a certain niche industry or leverages strong referrals, the inherent strength of that source may remain stable regardless of minor compensation adjustments.

In contrast, the number of applicants, quality of candidates, and time to hire are all more directly impacted by compensation changes. Higher pay often attracts more applicants and can improve the quality of candidates applying, while competitive salaries can also affect the urgency and speed with which candidates accept offers, thus influencing the time to hire.

Overall, the source of hire stands out as being less sensitive to fluctuations in compensation, making it the most suitable choice in this context.