There is a common conception amongst coffee drinkers (including myself) that drinking coffee increases productivity in office jobs. Is this true? Have there been any definitive studies which link caffeine consumption to productivity?

This is the closest study I could find. I can't access the full article, so I really don't know how they came to those surprising results: http://europepmc.org/abstract/med/582796

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    Seems like the answer here may be profession-specific. For example, the issue seems to be pretty decisive for truck drivers who wants to do a non-stop 24-hour trip, while it'd presumably be less clear for people who work relatively short shifts, especially in jobs where performance isn't meaningfully affected by wakefulness.
    – Nat
    Sep 13, 2017 at 23:45
  • It'd be interesting to consider cases like researchers. I often find that long, uninterrupted work cycles tend to result in above-linear performance improvements, e.g. 1 16-hour session is far more fruitful than 2 8-hour sessions, largely due to getting in a "zone" that's lost upon interruption (including sleep), such that stimulants can be incredibly helpful. But for easier workflows where it's not necessary to be in "the zone", work output tends to be more linear.
    – Nat
    Sep 13, 2017 at 23:56
  • I have no doubt that caffeine helps to prevent sleep, but I'm not sure if it's useful either in inducing flow or 'the zone'. I'm not sure if it would really have much of an effect either positively or negatively.
    – DaraJ
    Sep 14, 2017 at 1:40
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    I like the topic in the question, I just suspect that it's going to be complex to answer well. The issue's just that caffeine's very obviously useful to some workflows (e.g. driving a truck non-stop for a day) while it's pretty obviously not useful in other workflows (e.g. warm-body jobs where simply being present is most of the job) and perhaps even harmful in others (e.g. jobs requiring steady hands), with all sorts of in-betweens for different jobs, workflows, and people. To narrow it down, did you have a specific job or workflow in mind?
    – Nat
    Sep 14, 2017 at 2:52
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    Tangentially, I'd note that the linked study's from 1979. In general I'd recommend staying away from papers published before 2000 unless you're specifically looking for a historical perspective. There's a rather large quality issue with the soft sciences that only gets worse as we go back in time; the issue persists with even modern-day studies, but at least the bar's a bit higher now.
    – Nat
    Sep 14, 2017 at 3:00

1 Answer 1


One study has made an analysis of the effects of caffeine on cognitive performance. See: https://libres.uncg.edu/ir/uncw/f/lothesj2004-2.pdf

I didn't read the whole study but it seems that has tested with coffee capsules, placebos and beverages with different amounts of coffee. The results are not totally clear even for the author.

Although it is likely that caffeine in beverage form did have time to reach a peak levels of absorption and might be an explanation for why the 2mg/kg caffeine coffee group scored higher than the caffeinated capsule groups, it still does not help to explain why the decaffeinated coffee group also scored better than most of the capsule groups*. Nor does it explain why performance on the second task in this study did not produce significant effects since better caffeine absorption should have occurred.

*Highlighted by me

An interesting point that he remarks in conclusions is the diversity of results in many studies and why could that happen.

Many studies of caffeine effects on cognition have been conducted. However, these studies have produced mixed results. One potential reason for these conflicting results is because mixed procedural standards have been used, and in some cases they lack control over critically relevant variables

Page 37

Anyways, this is a good study that can point you to the right direction. The study mentions many other studies that can also be interesting.

I need to say that I couldn't find the name of the author or a reference page, only mention of other studies (I didn't search so much...)

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    Errr... isn't the explanation quite obvious? If both the caffeinated coffee group and the decaf coffee group scored better than the capsule group... "perhaps" it's the hot beverage that increases comfort and productivity? That would also match up with no significant increase in the second task -- as it's not the caffeine at work in the first place. So... anyone for a hot cocoa?
    – DevSolar
    Jan 21, 2019 at 9:02
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    @DevSolar It may be a placebo effect relating to coffee-like beverages, too.
    – T. Sar
    Jan 21, 2019 at 15:03
  • @DevSolar, agreed. Anecdotally, for many years I had several cups of coffee throughout the day at work, and definitely believe that I functioned better than on those days when I didn't have the drink. But, it was always decaffeinated coffee. Nov 27, 2019 at 19:06

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