In this post I would like to briefly discuss differences between self-quantification and self-tracking. These two terms are sometimes confused with one another because they both concern with measurement. To me, however, they are conceptually different, and seeing them used interchangeably kind of bothers me.
The modern dictionaries define quantification as “the act of discovering or expressing the quantity of something”. In other words, quantification is an act of expressing something in terms of numbers. Sometimes, it is extended to include categories, as well. For instance, one can “quantify” daily water intake in terms of milliliters or ounces (numerically), or as “insufficient”, “sufficient”, “excessive” (categorically). Such process of quantifying can be carried out either without involvement of the subject (passive quantification), or with subject’s help (active quantification). For instance, I can measure my heart rate either old-fashioned way (by finding my pulse on the artery and counting beats), or use an app (e.g., Instant Heart Rate or heart-rate monitor (e.g., Polar FT7 Heart Rate Monitor Depending on the nature of the variable, quantification can be done once (e.g., DNA analysis through 23andMe) or on a more frequent basis.
Consequently, self-quantification refers to quantification of self: expressing various aspects of self in terms of numbers or categories. We quantify our mood, physical activity, diet, sleep, career, productivity, relationships.. you name it. In fact, it is the ultimate purpose of Measured Me experiment to demonstrate that we can quantify any aspect of our everyday life.
The self-tracking (aka life logging), on the other hand, is a continuous and regular process of recording (aka logging) variables of interests and storing that data for further exploration. The data may not necessarily be quantitative or categorical; it could be pictures, videos, audio, twitter or Facebook updates, etc. For instance, in addition to quantitative information, I have been keeping a short diary using Momento app and tracking my location using Open Paths app.
Furthermore, in case of self-tracking, data are always logged on a relatively frequent basis. Depending on the rate of change or availability of measurement instruments, some variables need to be logged on a continuous basis (e.g., calories burned), several times a day (e.g., mood), once or several times a week (e.g., weight, body fat), or monthly (e.g, savings).
Thus, self-tracking does not always mean self-quantification: one can log his/her life by taking pictures, keeping a conventional diary or or even posting updates on Twitter (although you can always turn that unstructured data into numbers and categories, by rating sentiments, counting likes, etc.) Finally, not all self-quantification methods are suitable for self-tracking. Take for example happiness. I am pretty sure one can quantify happiness by analyzing activity of certain areas of the brain using CAT or MRI scan. But such method won’t be practical for tracking happiness on a regular basis in everyday settings. To my knowledge, the only available method to log happiness“on the go” is by logging it manually.