In the Star Trek TOS episode Where No Man Has Gone Before (the second episode made), we find out that Starfleet personnel files include a section on extrasensory perception (ESP) that apparently consists of both a quantitative ("esper rating") and narrative summary of the crew member's achievement or potential in ESP.

After this early episode, we see references to various abilities that could be considered forms of ESP, but I don't recall ever seeing any further references to Starfleet formally assessing and documenting the extrasensory capacities of its personnel.

Were the ESP evaluations referenced in that early episode something special or temporary (e.g. specifically ordered as part of the specific mission in that episode), or do all Starfleet personnel receive ESP evaluations, e.g. during their time at Starfleet Academy or during regular personnel reviews? For example, does Janeway have an esper rating somewhere in her file? I assume that Deanna Troi would rate above-average or even high, but do we ever get any notion that she received a formal ESP evaluation in the way that Dehner did?

Just to be clear, I'm not asking about the presence of ESP or ESP-like powers in Star Trek, only the formal ESP assessment referenced in the second episode of TOS.

Even a throwaway line could count as an answer. For example, if Worf makes a random comment that, "You know, Captain Picard had the lowest esper rating I've ever seen in an Academy graduate.", that would be an answer.

  • Another thing that is eyebrow raising is Dehner's speech about making better humans. It's a retcon but in-universe she was sounding like one of those eugenics nuts from the 1970s that thought world peace through genetic supermen would work. Jul 30, 2021 at 14:10
  • @RobertColumia It is spossible that the United Earth government and/or the Federation government as a whole, and/or private organzations, compile the files on esper abilities for some or all citizens. The Enterprise library computer has a vast amount of information available, which no doubt includes much information from many Federation government and civilian databases. I think that assuming that Starfleet complied the esper ratings is making an unproven assumption. Jul 30, 2021 at 16:53
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    ESP was quite a popular trope in the 1960s and 1970s (like psychiatry as in the 1940s thru early 1960s).
    – RonJohn
    Jul 31, 2021 at 16:08
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    Were the ESP evaluations referenced in that early episode something special or temporary (e.g. specifically ordered as part of the specific mission in that episode) Contextually, they seem to have been routine and not mission-specific. Dehner was a recent addition to the crew; the personnel records containing hers and Mitchell's ESP ratings contained general biographical information in a similar format, and there was no indication that ESP would have any bearing on the mission of the day until the Valiant's data recorder was retrieved. Jul 31, 2021 at 17:48

2 Answers 2


At least one other individual was assessed for some sort of ESP rating, the Betazoid telepath Tam Elbrun.

PICARD (V.O.): My immediate concern is with Tam Elbrun. Starfleet considers his unique abilities crucial to our mission. Yet he seems to me... unstable.

BEVERLY: Well, according to his medical records and psych profile, he's very high on the ESP scale. A sort of prodigy.

TNG: Tin Man


ESP ratings were never mentioned again in either TNG, DS9, VOY, ENT, the various TNG movies, or, to the best of my knowledge, through at least Star Trek Into Darkness reboot series.

(I cannot speak to anything post-Into Darkness, because that's where the franchise lost me.)

Therefore, it is possible -- but highly unlikely -- it has appeared in Picard, Lower Decks, Discovery, or the remaining "Kelvin timeline" film Star Trek Beyond.

Source: my own memory, plus I searched the incomparable Ex Astris Scientia site for "ESP" and got no hits beyond the already-mentioned "Where No Man Has Gone Before" episode.

(Edited to add: except, of course, for Tam Elbrun in TNG Tin Man, because well, my memory is not perfect and I forgot that line. So Valorum has it. But I can say that the ESP ratings never appeared in any of the formatted Starfleet LCARS "character bios" screens that were shown in TNG/DS9/VOY/ENT.)

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