The Personal Quantification Bias: How Tracking Makes Life Worse Even When You Choose It Freely

What the research on motivation says about quantifying behavior

Riikka Iivanainen
12 min readMar 2, 2023

If you’ve ever owned a fitness tracker, you know what it’s like to begin a workout realizing there’s nothing on your wrist (or finger). It’s like the modern-day version of the classic thought experiment “If a tree falls in a forest”: If you work out but don’t have any data on it, did it happen?

It’s frustrating for sure: “You should’ve put the tracker back on your wrist after the shower, you dummy!” But overall the benefits of tracking outweigh the costs of focusing a little more on the outcome of your workouts, daily activity, and sleep. Right?

That’s something I wondered about when I stopped tracking a few years ago. And then I forgot about it until I found myself debating the topic with my friends at a recent party.

To settle the debate (at least in my head), I looked up the research on personal quantification. And when I started reading, I realized I had found a fascinating topic touching on some fundamental questions regarding human motivation.

A painting of a seaside house with numbers on the canvas.
Painting by numbers? Andy Warhol, Do It Yourself (Seascape) (1962). © Andy Warhol. Image found on artnet.

To track or not to track?

After wearing an activity bracelet for almost a year in 2017, I had gradually grown addicted to my health data. I would peak at my heart rate readings multiple times during a workout, compare the average daily step counts between January and July, and scrutinize the sleep graphs which showed I was waking up numerous times throughout the night.

“Yes, the data was interesting. But it seemed to be distracting me from the main thing: enjoying the challenge of a HIIT workout, the sunrise on a morning walk, or just getting on with my life regardless of a bad night of sleep.”

Yes, the data was interesting. But it seemed to be distracting me from the main thing: enjoying the challenge of a HIIT workout, the sunrise on a morning walk, or just getting on with my life regardless of a bad night of sleep.

When the skin on my wrist became irritated from wearing the tracker day and night, I decided to take a few weeks’ break from it. A few weeks turned into years.

I didn’t plan to get back to tracking; I was happy with my decision. But when I began to jog regularly again, all of a sudden I became curious about my heart rate and speed. So last summer, I purchased a chest strap that synced with an exercise app.

The strap seemed like a sensible alternative to an activity bracelet or a smartwatch or ring. I could only view the data after the run (I don’t check my phone while out) and track nothing but exercise (I’m happily oblivious of my varying sleep quality).

But when I mentioned my recent purchase at a party, a friend of mine who runs a lot — and I mean a lot (he runs instead of using public transportation; he even ran to the party and back) — started questioning my need to track. He was adamant that paying attention to how you feel during and after the run suffices as feedback.

I tried to explain that I was simply curious to see if and how I was progressing, but he remained skeptical. When it felt like the party mood was taking a hit from the rigid discussion, another friend of mine joined in with a smirk on his face: “Well to me the best part about running is coming home and getting to play with my running spreadsheet.”

I was happy someone broke the tension with humor, but over the following weeks the conversation kept bothering me. Who was right? The friend who saw tracking as futile? The one who got joy from his running spreadsheet? Or me who fell somewhere in between?

Tracking boosts outputso all well and good?

The research on the impact of behavioral tracking appears fairly unanimous: You do more of the activities you track. For example, people who monitor the number of steps taken or pages read walk more and read more than the ones who don’t¹. One systematic review recounts that people who wear a pedometer increase their physical activity by an average of 27 %².

“The research on the impact of behavioral tracking appears fairly unanimous: You do more of the activities you track.”

Presumably due to these output-boosting results, most studies are positively biased towards tracking. For instance, one paper found an “extreme focus on numerical goals and numerical data” in tracker users, but instead of being alarmed, the authors go on to discuss the importance of data accuracy³. Even studies that specifically look at the downsides of wearables⁴ or the reasons for abandoning them⁵ conclude with design suggestions for overcoming weaknesses or encouraging continued use.

Professionals working in the field seem to think similarly. A health psychologist we consulted at work last year viewed behavioral tracking as the most effective tool for maintaining a habit like exercise. When I shared my concerns about the downsides of tracking, he waved them off as negligible.

Most academics and professionals don’t seem to be questioning the value of personal quantification. But some journalists and regular people tracking their behavior have pointed at the potential risks.

If tracking is all fun and games, what’s with the cautionary tales?

When you google “downsides of personal quantification”, you can find many articles, blog posts, and Quora discussions talking about the dangers of tracking. I picked out three examples:

In a The Washington Post column, Ellie Krieger describes how a calorie counting monitor changed her experience in spin class: “Before the devices were installed on the bikes’ handlebars, I would lose myself completely during a session — –. But the numbers on the monitor changed the game. Glancing at them throughout the class killed my euphoria and made me feel like a loser who couldn’t keep up.”

In a Quora thread to the question “What is the downside or negative impact of quantified-self and self-tracking?” one user tells the story of Alan who hasn’t missed a day of meditation for 324 days. On a day he almost forgets to meditate, all he thinks about during his 10-minute session is whether his streak will remain intact.

A BBC article tells the story of Lara who received an activity tracker from her employer: “At first it motivated me, but after a few weeks, it felt like I wasn’t running to feel good; I was doing it to log onto the app. It made me lose sight of how to take a rest day and relax.”

Clearly, tracking isn’t all fun and games. In fact, it appears to be killing the fun and turning an enjoyable activity into an all too serious game. Fortunately, we don’t only need to rely on lay people’s experiences to understand the effects of personal quantification.

The hidden cost of personal quantification

In a paper awarded the Journal of Consumer Research Best Article Award in 2019¹, Jordan Etkin explores the “hidden cost” of personal quantification. Through six experiments with varying activities (walking, reading, coloring) she shows that while quantifying a behavior increases output, it reduces enjoyment. For example, when research participants could view the number of shapes they had colored, they colored more shapes than the ones who couldn’t view this information, but also reported enjoying the experience less.

“While quantifying a behavior increases output, it reduces enjoyment.”

Slightly less enjoyment but more output — so what? Perhaps that’s the price you pay for getting those five runs in every week or reading 40 books a year. Unfortunately, tracking appears to have other negative effects as well.

In addition to reduced enjoyment, Etkin found a negative impact on subjective well-being. The participants who engaged in tracked activities, like walking with a pedometer, reported feeling less happy and satisfied afterwards.

What’s more, it made people less engaged when the measurement data was removed. For example, research participants who had been able to view the page number while reading a book excerpt read less when the “official” experiment was over and they were offered the opportunity to keep reading — this time with no page number visible.

These results eerily resemble the cautionary tales found online. But to truly understand what’s driving them, we’ll need to look into the research on intrinsic motivation.

A painting of a sailing boat with numbers on the canvas.
Andy Warhol, Do It Yourself (Sailboat) (1962). Image courtesy of the Andy Warhol Museum, Pittsburgh, © The Andy Warhol Foundation for the Visual Arts, Inc. Image found on artnet.

Measurement dataan extrinsic reward?

It’s well researched that introducing external rewards to an intrinsically motivated behavior makes people do less of it when the rewards are removed. In a classic experiment from the 1970s⁶, children who were rewarded for coloring shapes colored less in a subsequent session; their interest to engage in an inherently enjoyable activity had declined.

This phenomenon, coined the overjustification effect, is thought to be driven by a shift in perceived causality: Receiving a reward makes people infer that perhaps they didn’t engage in the activity for its own sake after all; they did it to receive money or prizes after the activity.

Interestingly, more recent experiments have found a reverse effect when attention is shifted towards the activity itself or its immediate rewards (vs. its delayed benefits). In one study, gym goers who paid attention to the experience of exercising had more fun and spent a longer time on the treadmill compared to the ones thinking about what they can achieve by working out⁷. In another study, research participants finished more sets when they selected a workout based on how much they liked it as opposed to what they could get from it⁸.

Recent theoretical developments help make sense of these findings. According to them, intrinsic motivation results from the activity and its goal overlapping⁹.

Let’s take my beloved hobby climbing as an example. If I go bouldering so that I can solve physical “problems” and hang out with friends, I’m intrinsically motivated; but if I go bouldering so that I can someday effortlessly climb a challenging 7B route, I’m extrinsically motivated. In the former, I’m reaching my goals while climbing, and in the latter, in the unforeseeable future (if ever).

But what does all this have to do with personal quantification?

“When we monitor the number of steps taken or calories burnt we draw attention to output — and away from the activity itself. This shift in attention makes the activity feel more like work.”

Well, measurement data acts like an extrinsic reward. When we monitor the number of steps taken or calories burnt we draw attention to output — and away from the activity itself. This shift in attention makes the activity feel more like work¹. Consequently, we enjoy ourselves less and become less engaged when the rewards are removed.

The picture I’ve painted of behavioral tracking so far is pretty dark. “Are there any exceptions to the rule?” you may be asking. Well, kind of.

But wait, is tracking always detrimental?

There are some factors that determine how detrimental it is to quantify an activity. One of them is framing.

“When an activity is framed as work-like to begin with, measurement data doesn’t reduce enjoyment or well-being.”

When an activity is framed as work-like to begin with, measurement data doesn’t reduce enjoyment or well-being. For example, when a reading task was framed as useful for learning, and hence work-like (and extrinsically motivated), tracking the number of pages read didn’t affect how much participants enjoyed it¹.

This is in line with previous research on the impact of external rewards. If the reward, such as money, is perceived as inherent to the pursued activity, it increases intrinsic motivation¹⁰. Thus, gambling and trading are exciting precisely because of the dollars and euros involved. In a competition, the possibility of winning the gold medal most likely amps up the excitement. But when it comes to factors external to the activity the research is more dispersed.

There is some evidence that individual differences play a role in how dark the dark side of personal quantification gets. People low in the Big Five personality traits conscientiousness and openness may experience more negative emotions related to behavioral tracking¹¹. On the other hand, individuals high in intrinsic motivation for physical activity and tracker usage (i.e., the desire to geek about performance data as opposed to the desire to lose weight) may not grow as dependent on their wearables¹². So perhaps my nerdy friend who loves playing with his running spreadsheet was onto something.

Unfortunately, some of the downsides seem to fall on everyone regardless of personality or preference. In one of Etkin’s experiments the vast majority decided to wear a pedometer when offered the choice to opt in or out¹. Getting to choose freely didn’t, however, protect people from the negative effects of viewing measurement data; it resulted in an equal decline in enjoyment and continued engagement compared to the condition in which participants were simply assigned to use a pedometer.

“Even when you feel eager to track your workouts, you may be harming your enjoyment and persistence — essentially, your intrinsic motivation.”

This is the spooky side of personal quantification. Even when you freely choose to track your workouts (and aren’t forced to do it like when the calorie monitors are attached to the spin bikes’ handlebars), you may be harming your enjoyment and persistence — essentially, your intrinsic motivation. Perhaps we should call it the personal quantification bias.

Now that we’ve looked at the evidence, we can finally try and settle the debate at the party.

If you want to play it safe, don’t quantify your behavior

Who was right? The hard-core runner, the data lover, or me?

I would say my runner friend was. If you want to enjoy your runs (or your reading or painting sessions), retain your natural engagement levels, and feel happier overall, you’re better off not quantifying them.

“My friend’s advice to pay attention to how you feel during the run and immediately after is supported by the evidence; it can increase intrinsic motivation.”

In fact, my friend’s advice to pay attention to how you feel during the run and immediately after is supported by the evidence; it can increase intrinsic motivation⁷. (Perhaps not tracking reinforces his desire to choose feet over wheels when moving from place A to B.)

Obviously, we need more research on the effects of personal quantification. But the lack of truly long-term studies does call for caution². We don’t know what happens to motivation if you continue tracking for years or if you yo-yo between using and not using wearables (or other tools for quantifying behavior).

Researching and writing this article definitely made me more hesitant to collect numerical data on my hobbies. Since I’m not a professional athlete (and not even training for a marathon, or a 10 k for that matter) I don’t really need to know how fast I run or what my heart rate is; I just want to stay healthy and have fun.

So in 2023, I’ve gladly forgotten my chest strap at home. I’ve even decided not to set a reading goal on Goodreads. And if I was asked to join a health initiative at work that involves tracking, I would probably say no.

Despite having the science on my side, I occasionally notice a slight sting in my chest. How do I know how my runs are going? Will I read a lot fewer books this year?

I guess it’ll take some time to adapt to the absence of numbers. But if it results in more joy and satisfaction, I’m happy to give it a try. And when I go for a run or read a book, I will know I did it. I don’t need data to tell me so.


  1. Etkin, J. (2016). The Hidden Cost of Personal Quantification. Journal of Consumer Research, 42(6), 967–984.
  2. Bravata, D. M., Smith-Spangler, C., Sundaram, V., Gienger, A. L., Lin, N., Lewis, R., Stave, C.D., Olkin, I. & Sirard, J. R. (2007). Using Pedometers to Increase Physical Activity and Improve Health: A Systematic Review. Jama, 298(19), 2296–2304.
  3. Fritz, T., Huang, E. M., Murphy, G. C., & Zimmermann, T. (2014, April). Persuasive Technology in the Real World: A Study of Long-Term Use of Activity Sensing Devices for Fitness. In Proceedings of the Sigchi Conference on Human Factors in Computing Systems (Pp. 487–496).
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  8. Woolley, K., & Fishbach, A. (2016). For the Fun of It: Harnessing Immediate Rewards to Increase Persistence in Long-Term Goals. Journal of Consumer Research, 42(6), 952–966.
  9. Fishbach, A., & Woolley, K. (2022). The Structure of Intrinsic Motivation. Annual Review of Organizational Psychology and Organizational Behavior, 9, 339–363.
  10. Kruglanski, A. W., Riter, A., Amitai, A., Margolin, B. S., Shabtai, L., & Zaksh, D. (1975). Can Money Enhance Intrinsic Motivation? A Test of the Content-Consequence Hypothesis. Journal of Personality and Social Psychology, 31(4), 744.
  11. Ryan, J., Edney, S., & Maher, C. (2019). Anxious or Empowered? A Cross-Sectional Study Exploring How Wearable Activity Trackers Make Their Owners Feel. BMC Psychology, 7, 1–8.
  12. Attig, C., & Franke, T. (2019). I Track, Therefore I Walk–Exploring the Motivational Costs of Wearing Activity Trackers in Actual Users. International Journal of Human-Computer Studies, 127, 211–224.



Riikka Iivanainen

Writer, content designer, and user researcher fascinated by the human mind and behavior. I study (social) psychology for fun and love to tell stories.