The Quantified Self, also known as lifelogging, is a movement to incorporate technology into data acquisition on aspects of a person's daily life in terms of inputs (food consumed, quality of surrounding air), states (mood, arousal, blood oxygen levels), and performance, whether mental or physical. In short, quantified self is self-knowledge through self-tracking with technology.
Data collection through self-monitoring and self-sensing combines wearable sensors (e.g. EEG, ECG) and wearable computing. Among the specific biometrics one can track are insulin and cortisol levels, sequence DNA, and the microbial cells which inhabit one's body.
According to Riphagen et al., the history of the quantimetric self-tracking using wearable computers began in the 1970s:
"The history of self-tracking using wearable sensors in combination with wearable computing and wireless communication already exists for many years, and also appeared, in the form of sousveillance back in the 1970s [13, 12]"
Quantimetric self-sensing was proposed for the use of wearable computers to automatically sense and measure exercise and dietary intake in 2002:
"Sensors that measure biological signals, ... a personal data recorder that records ... Lifelong videocapture together with blood-sugar levels, ... correlate blood-sugar levels with activities such as eating, by capturing a food record of intake."
The “quantified self” or “self-tracking” are contemporary labels. They reflect the broader trend of the progressions for organization and meaning-making in human history; there has been a use of self-taken measurements and data collection that attempted the same goals that the quantified movement has. Scientisation plays a major role in legitimizing self-knowledge through self-tracking. As early as 2001, media artists such as Ellie Harrison and Alberto Frigo extensively pioneered the concept, proposing a new direction of labour-intensive self-tracking without the use of any privacy infringing automation.
The term "quantified self" appears to have been proposed in San Francisco, CA, by Wired Magazine editors Gary Wolf and Kevin Kelly in 2007 as "a collaboration of users and tool makers who share an interest in self knowledge through self-tracking." In 2010, Wolf spoke about the movement at TED, and in May 2011, the first international conference was held in Mountain View, California. There are conferences in America and Europe. Gary Wolf said "Almost everything we do generates data." Wolf suggests that companies target advertising or recommend products use data from phones, tablets, computers, other technology, and credit cards. However, using the data they make can give people new ways to deal with medical problems, help sleep patterns, and improve diet.
Philosophers like Michel Foucault are recognized as being a part of the foundations in the ideas of the quantified movement. Foucault and other philosophers focus on the idea of “care of the self,” in which they emphasize the importance of self-knowledge for personal development. Foucault explains that it involves looking inside oneself and emphasizes self-reflection, which is also associated with the quantified self movement, where self-tracking participants can attend “show-and-tell” style conventions to share their experiences with the technology.
Today the global community has over a hundred groups in 34 countries around the world, with the largest groups in San Francisco, New York, London, and Boston having over 1500 members each.
Like any empirical study, the primary method is the collection and analysis of data. In many cases, data are collected automatically using wearable sensors -not limited to, but often worn on the wrist. In other cases, data may be logged manually.
The data are typically analyzed using traditional techniques such as linear regression to establish correlations among the variables under investigation. As in every attempt to understand potentially high-dimensional data, visualization techniques can suggest hypotheses that may be tested more rigorously using formal methods. One simple example of a visualization method is to view the change in some variable – say weight in pounds – over time.
Even though the idea is not new, the technology is. Many people would track what they would eat or how much physical activity they got within a week. Technology has made it easier and simpler to gather and analyze personal data. Since these technologies have become smaller and cheaper to be put in smart phones or tablets, it is easier to take the quantitative methods used in science and business and apply them to the personal sphere.
Narratives constitute a symbiotic relationship with bodies of large data. Therefore, quantified self participants are encouraged to share their experiences of self-tracking at various conferences and meetings.
A major application of quantified self has been in health and wellness improvement. Many devices and services help with tracking physical activity, caloric intake, sleep quality, posture, and other factors involved in personal well-being. Corporate wellness programs, for example, will often encourage some form of tracking. Genetic testing and other services have also become popular.
Quantified self is also being used to improve personal or professional productivity, with tools and services being used to help people keep track of what they do during the workday, where they spend their time, and who they interact with.
One other application has been in the field of education, with wearable devices being used in schools so that students can learn more about their own activities and related math and science.
Many start-up companies occupy the market right now[when?]. Most of them help track data for some type of health pattern, be it sleep or asthma. However, there are bigger companies such as Nike, Jawbone, and FitBit that occupy some of the space in the market.
A recent movement in quantified self is gamification. There are a wide variety of self-tracking technologies that allow everyday activities to be turned into games by awarding points or monetary value to encourage people to compete with their friends. The success of connected sport is part of the gamification movement. People can pledge a certain amount of real or fake money, or receive awards and trophies.
Many of these self-tracking applications or technologies are compatible with each other and other websites so people can share information with one another. Each technology may integrate with other apps or websites to show a bigger picture of health patterns, goals, and journaling. For example, one may figure out that migraines were more likely to have painful side effects when using a particular migraine drug. Or one can study personal temporal associations between exercise and mood.
The quantified self is also demonstrating to be a major component of “big data science", due to the amount of data that users are collecting on a daily basis. Although these data set streams are not conventional big data, they become interesting sites for data analysis projects, that could potentially be used in medical-related fields to predict health patterns or aide in genomic studies. Examples of studies that have been done using QS data include projects such as the DIYgenomics studies, the Harvard’s Personal Genome Project, and the American Gut microbiome project. 
Quantified Baby is a branch of the Quantified Self movement that is concerned with collecting extensive data on a baby's daily activities, and using this data to make inferences about behaviour and health. A number of software and hardware products exist to either assist data collection by the parent or collect data automatically for later analysis. Reactions to "Quantified Baby" are mixed.
Parents are often told by health professionals to record daily activities about their babies in the first few months, such as feeding times, sleeping times and nappy changes. This is useful for both the parent (used to maintain a schedule and ensure they remain organised) and for the health professional (to make sure the baby is on target and occasionally to assist in diagnosis). For quantified self, knowledge is power, and knowledge about oneself easily translates as a tool for self-improvement. The aim for many is to use this tracking to ultimately become better parents. Some parents use sleep trackers because they worry about sudden infant death syndrome.
A number of apps exist that have been made for parents wanting to track their baby's daily activities. The most frequently tracked metrics are feeding, sleeping and diaper changes. Mood, activity, medical appointments and milestones are also sometimes covered. Other apps are specifically made for breastfeeding mothers, or those who are pumping their milk to build up a supply for their baby.
Devices and services
Notable self-quantification tools are listed below. Numerous other hardware devices and software are available, as a result of advances and cost reductions in sensor technology, mobile connectivity, and battery life.
- Apple Watch
- Garmin activity trackers
- BodyMedia FIT – skin temperature, galvanic skin response; acquired by Jawbone in April 2013
- Fitbit Tracker – steps taken, stairs climbed, distance traveled, calories burned, sleep quality, heart rate
- Instant App - Automatically tracks activities: Phone/app usage, fitness, places, travel & sleep
- Jawbone UP – steps taken, calories burned, eating habits, sleep quality and sleep cycle vibration alarm; behavioral nudges (water consumption, movement, sleep)
- Nike+ FuelBand – steps taken, calories burned. To be discontinued.
- Razer Nabu – sleep, steps you've walked, distance travelled, calories burnt, and active start and stop time
- Pebble – motion and sleep tracking.
- QardioCore – ECG, activity, body temperature monitoring
- Samsung Gear Fit – heart rate, pedometer, accelerometer; notifications from compatible phones
- Technogym – display a "performance index" in conjunction with a heart rate monitor
- Weight Watchers ActiveLink - accelerometer-based activity tracking with estimation of calorie consumption
- Zephyr BioHarness – complex physiological monitoring
- Simband – open source physiological monitoring
- Misfit Wearables – activity and sleep monitoring (tracking step count, calories burned, distance traveled, and number of hours of light and deep sleep)
- SleepBot – a freeware app, for Android and iOS
- WakeMate – a wristband plus an accompanying app
- Zeo – a sleep-monitoring headband
Diet and weight
- 23andMe – genetics
- BACtrack – alcohol intake and its effect on the body
- dacadoo Health Score and platform for behavioral change
- QardioArm Smart Blood Pressure Monitor
- uBiome – personal microbiome
- Thriva - blood test
- Lioness - a vibrator that tracks sexual response
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