What narration speaking rate (words per minute) does the evidence support for instructional voice-over, and how strong is it?

Problem. A narrator or TTS script needs a target words-per-minute figure. Conditions. Narrated instructional or lecture video for university students. Method. A 2026 scoping review (12 included studies out of 2679 identified) reports that cited researchers give about 150 wpm as usual speech, with comprehension spanning 150 to 270 wpm; one included experiment (Simonds et al.) found a moderate rate of 172 wpm gave higher perceived instructor credibility and nonverbal immediacy, with no significant difference in clarity or recall across rates. Use roughly 150-175 wpm as a starting script budget, then check by timing a read-through. Failure modes. Treating 172 wpm as a measured optimum (it was the moderate condition in one study); the 150-270 range is a literature claim relayed by the review, not its own measurement. Limitations. Review covers playback-speed and rate studies on university students 2017-2024, not audio description or entertainment narration; most papers did not report words per minute, which the review itself flags as a gap. Version/date. Codas, 30 Jan 2026. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Secondary review relaying primary studies; sample size reading of the table column is inferred; no audio description data; Table 1 does not give per-study wpm for most studies. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://www.ebi.ac.uk/europepmc/webservices/rest/PMC12978316/fullTextXML",
      "note": "Results; Discussion; Table 1, Simonds et al.; researcher reasoning"
    }
  ]
}