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categories: ["enhancement", "society"]categories: ["enhancement", "society"]tags: ["self-tracking", "measurement", "n-of-1", "privacy", "wearables", "citizen science"]tags: ["self-tracking", "measurement", "n-of-1", "privacy", "wearables", "citizen science"]summary: "A movement and a method for learning about oneself through personal measurement, built on n-of-1 self-experiment and named by two Wired editors in 2007."summary: "A movement and a method for learning about oneself through personal measurement, built on n-of-1 self-experiment and named by two Wired editors in 2007."updated: "2026-07-27"updated: "2026-10-29"humanEvidence: "Self-monitoring raises measured activity in people over the short term; a randomised trial of a workplace wellness programme found more self-reported exercise but no change in clinical measures or spending at 18 months."humanEvidence: "Self-monitoring raises measured activity in people over the short term; a randomised trial of a workplace wellness programme found more self-reported exercise but no change in clinical measures or spending at 18 months."access: "Trackers ship in most phones and cost from tens to a few hundred dollars, but much tracking now arrives through an employer or insurer programme rather than a purchase."access: "Trackers ship in most phones and cost from tens to a few hundred dollars, but much tracking now arrives through an employer or insurer programme rather than a purchase."reversibility: "context"reversibility: "context"lines 23–29 → 23–299 unchanged lines not shown
{ "label": "Motto", "value": "Self-knowledge through numbers" }, { "label": "Motto", "value": "Self-knowledge through numbers" }, { "label": "Core method", "value": "n-of-1 self-experiment" }, { "label": "Core method", "value": "n-of-1 self-experiment" }, { "label": "Meetup format", "value": "Show-and-tell, three questions" }, { "label": "Meetup format", "value": "Show-and-tell, three questions" }, { "label": "Conference series", "value": "2011–2018" }, { "label": "Conference series", "value": "2011-2018" }, { "label": "Successor term", "value": "Personal science" }, { "label": "Successor term", "value": "Personal science" }, { "label": "Adjacent practice", "value": "Biohacking", "link": "/wiki/biohacking" } { "label": "Adjacent practice", "value": "Biohacking", "link": "/wiki/biohacking" } ] ]lines 75–87 → 75–8745 unchanged lines not shown
**Regression to the mean.** People start tracking when something is unusually bad: sleep at its worst, weight at its highest, mood at its lowest. The next measurement tends back toward the personal average whether or not anything was done, and an intervention begun at the trough inherits credit for the return.**Regression to the mean.** People start tracking when something is unusually bad: sleep at its worst, weight at its highest, mood at its lowest. The next measurement tends back toward the personal average whether or not anything was done, and an intervention begun at the trough inherits credit for the return. **Expectancy.** The person running the experiment is the person hoping it works, and is also the instrument reading the outcome. Where the endpoint is self-reported — energy, focus, sleep quality — this is close to unmanageable. Placebo research has found reported symptom improvement even when participants were told they were receiving an inert pill.**Expectancy.** The person running the experiment is the person hoping it works, and is also the instrument reading the outcome. Where the endpoint is self-reported, as with energy, focus or sleep quality, this is close to unmanageable. Placebo research has found reported symptom improvement even when participants were told they were receiving an inert pill. **Seasonality.** Activity, weight, sleep duration, mood and vitamin D all vary across the year. An experiment run from February to April is confounded with spring.**Seasonality.** Activity, weight, sleep duration, mood and vitamin D all vary across the year. An experiment run from February to April is confounded with spring. **Multiplicity.** Someone logging forty variables and looking for relationships among them will find several at conventional thresholds by chance alone. Self-trackers rarely pre-register a hypothesis, and the exploratory search is usually reported as though it had been a test.**Multiplicity.** Someone logging forty variables and looking for relationships among them will find several at conventional thresholds by chance alone. Self-trackers rarely pre-register a hypothesis, and the exploratory search is usually reported as though it had been a test. A fifth problem is peculiar to the practice: measurement changes the thing measured. Wearing a step counter increases steps. That reactivity is how tracking produces behaviour change in the short term, and also why a tracked baseline is not a baseline; whether the change survives beyond the short term is a separate question, and the randomised evidence on that, summarised under [[wearable-health-sensors]], is weak.A fifth problem is peculiar to the practice: measurement changes the thing measured. Wearing a step counter increases steps. That reactivity is how tracking produces behaviour change in the short term, and it is also why a tracked baseline is not a true baseline. Whether the change survives beyond the short term is a separate question, and the randomised evidence on that, summarised under [[wearable-health-sensors]], is weak. ## The instruments## The instruments lines 91–102 → 91–1023 unchanged lines not shown
## From choice to default## From choice to default The movement's odd fate is that it won and then disappeared. Tracking is no longer something a person decides to take up. Phones count steps without being asked, watches record heart rate continuously, US regulators cleared the first over-the-counter glucose sensor in 2024 for adults who do not use insulin, with others following within the year, and [[consumer-blood-testing|direct-to-consumer blood panels]] and [[biological-age]] reports are sold as retail products. The hobbyist device makers of the late 2000s were acquired or liquidated, and their function moved into general-purpose hardware.The movement's odd fate was to win and then disappear. Tracking is no longer something a person decides to take up. Phones count steps without being asked, watches record heart rate continuously, US regulators cleared the first over-the-counter glucose sensor in 2024 for adults who do not use insulin, with others following within the year, and [[consumer-blood-testing|direct-to-consumer blood panels]] and [[biological-age]] reports are sold as retail products. The hobbyist device makers of the late 2000s were acquired or liquidated, and their function moved into general-purpose hardware. Default tracking is a different thing from voluntary self-experiment, and the difference is who holds the data and who set the goal. Deborah Lupton's sociology of the practice distinguishes tracking that is private, communal, pushed, imposed and exploited, the last two covering employer wellness programmes, insurance schemes, and the resale of behavioural data by parties the tracked person never dealt with.[^lupton2016] A step count logged to answer a personal question and the same count logged to qualify for a premium discount are not the same measurement.Default tracking is a different thing from voluntary self-experiment, and the difference is who holds the data and who set the goal. Deborah Lupton's sociology of the practice distinguishes tracking that is private, communal, pushed, imposed and exploited, the last two covering employer wellness programmes, insurance schemes, and the resale of behavioural data by parties the tracked person never dealt with.[^lupton2016] A step count logged to answer a personal question and the same count logged to qualify for a premium discount are not the same measurement. > [!debate] Whether tracking improves outcomes> [!debate] Whether tracking improves outcomes> Two large randomised evaluations of workplace wellness programmes converged on the same answer. In a trial at a US retailer, employees offered the programme reported more regular exercise and more active weight management at 18 months, while clinical measures, health spending and employment outcomes did not differ significantly from controls.[^song2019] The Illinois study raised screening rates but found no significant effect on medical spending, other health behaviours or productivity, and it added a result that complicates every observational claim here: employees who chose to enrol were already healthier and lower-spending before the programme began, so such schemes look effective in uncontrolled data largely through selection.[^jones2019] Advocates answer that the interventions tested were weak, which is a fair point about those trials and not an argument that a stronger one works.> Two large randomised evaluations of workplace wellness programmes converged on the same answer. In a trial at a US retailer, employees offered the programme reported more regular exercise and more active weight management at 18 months, while clinical measures, health spending and employment outcomes did not differ significantly from controls.[^song2019] The Illinois study raised screening rates but found no significant effect on medical spending, other health behaviours or productivity, and it added a result that complicates every observational claim here: employees who chose to enrol were already healthier and lower-spending before the programme began, so such schemes look effective in uncontrolled data largely through selection.[^jones2019] Advocates answer that the interventions tested were weak. That is a fair point about those trials, but it does not show that a stronger programme works. ## Data, ownership and privacy## Data, ownership and privacy lines 106–118 → 106–1183 unchanged lines not shown
## Criticism## Criticism The sociological objection is that quantification does not merely describe a life but reshapes what counts in it, privileging whatever a sensor happens to capture and moralising health as personal diligence. Participants were disproportionately affluent, technically skilled and already healthy, which limits what their conclusions generalise to and ties the practice to [[access-and-inequality]]. Clinicians treating eating disorders have raised specific concerns about calorie- and step-counting features, which can supply a socially approved vocabulary for restriction.The sociological objection is that quantification reshapes what counts in a life as well as describing it, privileging whatever a sensor happens to capture and moralising health as personal diligence. Participants were disproportionately affluent, technically skilled and already healthy, which limits what their conclusions generalise to and ties the practice to [[access-and-inequality]]. Clinicians treating eating disorders have raised specific concerns about calorie- and step-counting features, which can supply a socially approved vocabulary for restriction. A narrower criticism concerns the yield. No self-tracking result has entered the physiology literature as an accepted finding, in contrast to the do-it-yourself insulin-delivery work described under [[biohacking]], which produced a technology and then a randomised controlled trial. Defenders answer that population knowledge was never the point, and that a method for answering a question about one person is valuable even if it generalises to nobody — a claim also made for individualised use of [[dietary-supplements]] and [[nootropics|cognitive supplements]].A narrower criticism concerns the yield. No self-tracking result has entered the physiology literature as an accepted finding, in contrast to the do-it-yourself insulin-delivery work described under [[biohacking]], which produced a technology and then a randomised controlled trial. Defenders answer that population knowledge was never the point, and that a method for answering a question about one person is valuable even if it generalises to nobody. The same claim is made for individualised use of [[dietary-supplements]] and [[nootropics|cognitive supplements]]. ## Outlook## Outlook The method has outlived the movement. Wolf and Martijn de Groot's framework recast the practice as "personal science", defining it by the process of asking and answering a personal empirical question rather than by any device.[^wolfdegroot2020] Rigorous n-of-1 designs have meanwhile found institutional homes in rare-disease therapeutics, chronic pain and precision nutrition, with denser data than the paper-diary era allowed. Whether that infrastructure serves the person wearing the sensor or the parties buying the exhaust is now a governance question rather than a technical one, and it will be settled by data-protection law and employment practice rather than by anything the [[human-enhancement|enhancement]] debate contributes. What the founders wanted — a person answering a question about their own body, with numbers, and telling others how it went — turned out to be the easy part.The method has outlived the movement. Wolf and Martijn de Groot's framework recast the practice as "personal science", defining it by the process of asking and answering a personal empirical question rather than by any device.[^wolfdegroot2020] Rigorous n-of-1 designs have meanwhile found institutional homes in rare-disease therapeutics, chronic pain and precision nutrition, with denser data than the paper-diary era allowed. Whether that infrastructure serves the person wearing the sensor or the parties buying the exhaust is now a governance question rather than a technical one, and it will be settled by data-protection law and employment practice rather than by anything the [[human-enhancement|enhancement]] debate contributes. The founders' aim, a person answering a question about their own body with numbers and telling others how it went, turned out to be the easy part. ## See also## See also lines 124–129 → 124–1305 unchanged lines not shown
- [[mental-privacy]]- [[mental-privacy]]- [[access-and-inequality]]- [[access-and-inequality]]- [[healthspan]]- [[healthspan]]- [[blueprint-protocol]] ## References## References removed, struck through added, underlinedLine numbers count the serialised markdown of each revision, frontmatter included.
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