Screening questions are the optional questions a client adds to an Upwork job post that every freelancer or agency must answer as part of their proposal, shown to the client beside the cover letter.
When writing a job post, the client can pick questions from a list Upwork suggests, such as describing a similar project or naming the tools they would use, or write their own. Upwork allows a limited number per post, a limit it sets and may change. The questions appear on the proposal form, each with its own answer box, and a proposal cannot be submitted with one left blank. On the client's side the answers are displayed with the cover letter, so a client comparing proposals can read the same answer from each applicant.
Clients use the questions as a filter. A letter can be templated but an answer to "which of our listed requirements have you not done before" is harder to fake, and clients who add questions tend to be the ones who read proposals properly. Answers that repeat the cover letter, or that are obviously pasted, are the fastest route to being archived.
For freelancers the questions are also a signal about the client: a post with thoughtful questions is usually a client who knows what they want and is likely to hire, which the hire rate in the client panel will often confirm. Screening questions are not a test in Upwork's sense; there is no scoring, and the answers are seen only by the client who asked them.
How Upwork Insights uses it
This term describes Upwork's own rules or product rather than a figure the index measures; the pages that do carry live figures are the stats and rate pages.