Time-use research

Time-use research is an interdisciplinary field of study dedicated to learning how people allocate their time during an average day. Work intensity is the umbrella topic that incorporates time use, specifically time poverty.

The comprehensive approach to time-use research addresses a wide array of political, economic, social, and cultural issues through the use of time-use surveys. Surveys provide geographic data and time diaries that volunteers record using GPS technology and time diaries. Time-use research investigates human activity inside and outside the paid economy. It also looks at how these activities change over time.

Time-use research is not to be confused with time management. Time-use research is a social science interested in human behavioural patterns and seeks to build a body of knowledge to benefit a wide array of disciplines interested in how people use their time. Time management is an approach to time allocation with a specific managerial purpose aimed at increasing the efficiency or effectiveness of a given process.

Questions relating to time-use research arise in most professional and academic disciplines, notably:

Categories of time

Time-use researcher Dagfinn Aas classifies time into four meaningful categories: contracted time; committed time; necessary time; and free time.[1]

Contracted time

Contracted time refers to the time a person allocates toward an agreement to work or study. When a person is using contracted time to commute this person understands that this travel time is directly related to paid work or study and any break in this commute time

Committed time

Committed time, like contracted time, takes priority over necessary and free time because it is viewed as productive work. It refers to the time allocated to maintain a home and family. When a person is commuting using committed time this person may feel that the commute is a duty to family such as walking children to school or driving a spouse to work. Contracted and committed time users may feel that their commute is more important than the commute of necessary or free time users because their commute is productive work. Therefore, they may be more inclined to choose a motorized mode of travel.

Necessary time

Necessary time refers to the time required to maintain one’s self as it applies to activities such as eating, sleeping, and cleansing and to a large extent exercising. People who commute using necessary time may feel that the commute is an important activity for personal well-being and may also take into account the well-being of the natural and social environment. The person commuting in necessary time may be more inclined to choose an active mode of transportation for personal reasons that include exercise on top of transportation.

Since sleeping is included in this category, necessary time usually constitutes the majority of people’s time.

Free time

Free time refers to the remains of the day after the three other types of time have been subtracted from the 24-hour day. This type of time is not necessarily discretionary time as the term “free” time may imply because people tend to plan activities in advance and creating committed free time in lieu of discretionary time. People who commute using free time are more apt to view the commute as a recreational activity. Commuting in free time provides the greatest gains for social capital because the person commuting in free time is more likely to slow down or stop the commute at his discretion to undertake another activity or engage in social interaction. He or she may also view the commute as part of his destination activity to which he has gladly committed his or her free time.

Primary vs. secondary time

The distinction between primary and secondary time is a way to include activities when multitasking. Activities that take place at the same time are separated into primary and secondary categories based on priority assigned to each, with the activity with the highest priority considered to be the primary. This distinction plays an important role when evaluating time spent on activities that often considered secondary when multitasking, as overlooking secondary activities can lead to significant underestimations of the time committed to those activities.

According to research in Australia, approximately two thirds of time spent on childcare is considered secondary time.[2] Research in the United States is more variable ranging from approximately one third[3][4] to approximately three fourths[5] of time spent on childcare being secondary time.

Primary time

Primary time refers to time spent on a primary activity only. The primary activity is the activity that has the highest priority. For example, the primary task when drinking coffee while working would be working and the time therefore classified as contracted time. Assigning priority to each activity is left up to the person recording their time usage and similar combinations of activities may be treated differently under different circumstances. While eating in front of a television, both eating and watching T.V. could be considered the primary activity depending on the circumstances.

Secondary time

Secondary time is the time spent on secondary or side activities. When drinking coffee while working, drinking coffee would be the secondary activity and would be considered necessary time even though the primary activity, working, would be classified as contracted time. Unlike primary time, secondary time does not necessarily add up to 24 hours each day because there may not always be a secondary activity. It is also important to note that including secondary time may make it appear that a person spends more than 24 hours a day on activities due to the overlapping nature primary and secondary time.


See also


  1. ^ Ås, Dagfinn (1978). "Studies of Time-Use: Problems and Prospects". Acta Sociologica. 21 (2): 125–141. JSTOR 4194228.
  2. ^ "How Australians Use Their Time." 4153.0. Australian Bureau of Statistics,21 Feb. 2008.Web.
  3. ^ John Robinson, and Geoffrey Godbey, Time for Life. The Surprising WaysAmericans Use Their Time (University Park: Pennsylvania State University,1997), 107
  4. ^ Keith W. Bryant and Cathleen D. Zick, “An Examination of Parent-Child Shared Time,” Journal of Marriage and the Family, 58 (1996): 227-237
  5. ^ Suzanne M. Bianchi, “Maternal Employment and Time with Children: Dramatic Change or Surprising Continuity?” Demography 37 (2000): 401-14

External links

24-hour clock

The 24-hour clock is the convention of time keeping in which the day runs from midnight to midnight and is divided into 24 hours, indicated by the hours passed since midnight, from 0 to 23. This system is the most commonly used time notation in the world today, and is used by international standard ISO 8601.A limited number of countries, particularly English-speaking, use the 12-hour clock, or a mixture of the 24- and 12-hour time systems. In countries where the 12-hour clock is still dominant, some professions prefer to use the 24-hour clock. For example, in the practice of medicine the 24-hour clock is generally used in documentation of care as it prevents any ambiguity as to when events occurred in a patient's medical history. In the United States and a handful of other countries, it is popularly referred to as military time.


An astrarium, also called a planetarium, is the mechanical representation of the cyclic nature of astronomical objects in one timepiece. It is an astronomical clock.

BPL (time service)

BPL is the call sign of the official long-wave time signal service of the People's Republic of China, operated by the Chinese Academy of Sciences, broadcasting on 100 kHz from CAS's National Time Service Center in Pucheng County, Shaanxi at 34°56′54″N 109°32′34″E, roughly 70 km northeast of Lintong, along with NTSC's short-wave time signal BPM on 2.5, 5.0, 10.0, and 15.0 MHz.

BPL broadcasts LORAN-C compatible format signal from 5:30 to 13:30 UTC, using an 800 kW transmitter covering a radius up to 3000 km.

Carpe diem

Carpe diem is a Latin aphorism, usually translated "seize the day", taken from book 1 of the Roman poet Horace's work Odes (23 BC).


Chronometry (from Greek χρόνος chronos, "time" and μέτρον metron, "measure") is the science of the measurement of time, or timekeeping. Chronometry applies to electronic devices, while horology refers to mechanical devices.

It should not to be confused with chronology, the science of locating events in time, which often relies upon it.

Clock position

A clock position is the relative direction of an object described using the analogy of a 12-hour clock to describe angles and directions. One imagines a clock face lying either upright or flat in front of oneself, and identifies the twelve hour markings with the directions in which they point.

Using this analogy, 12 o'clock means ahead or above, 3 o'clock means to the right, 6 o'clock means behind or below, and 9 o'clock means to the left. The other eight hours refer to directions that are not directly in line with the four cardinal directions.

In aviation, a clock position refers to a horizontal direction; it may be supplemented with the word high or low to describe the vertical direction which is pointed towards your feet. 6 o'clock high means behind and above the horizon, while 12 o'clock low means ahead and below the horizon.

Common year

A common year is a calendar year with 365 days, as distinguished from a leap year, which has 366. More generally, a common year is one without intercalation. The Gregorian calendar, (like the earlier Julian calendar), employs both common years and leap years to keep the calendar aligned with the tropical year, which does not contain an exact number of days.

The common year of 365 days has 52 weeks and one day, hence a common year always begins and ends on the same day of the week (for example, January 1 and December 31 fell on a Sunday in 2017) and the year following a common year will start on the subsequent day of the week. In common years, February has four weeks, so March will begin on the same day of the week. November will also begin on this day.

In the Gregorian calendar, 303 of every 400 years are common years. By comparison, in the Julian calendar, 300 out of every 400 years are common years, and in the Revised Julian calendar (used by Greece) 682 out of every 900 years are common years.


Endurantism or endurance theory is a philosophical theory of persistence and identity. According to the endurantist view, material objects are persisting three-dimensional individuals wholly present at every moment of their existence, which goes with an A-theory of time. This conception of an individual as always present is opposed to perdurantism or four dimensionalism, which maintains that an object is a series of temporal parts or stages, requiring a B-theory of time. The use of "endure" and "perdure" to distinguish two ways in which an object can be thought to persist can be traced to David Lewis.


HD2IOA is the callsign of a time signal radio station operated by the Navy of Ecuador. The station is located at Guayaquil, Ecuador and transmits in the HF band on 3.81 and 7.6 MHz.The transmission is in AM mode with only the lower sideband (part of the time H3E and the rest H2B/H2D) and consists of 780 Hz tone pulses repeated every ten seconds and voice announcements in Spanish.

While sometimes this station is described as defunct, reception reports of this station on 3.81 MHz appear regularly at the Utility DX Forum.

Intercalation (timekeeping)

Intercalation or embolism in timekeeping is the insertion of a leap day, week, or month into some calendar years to make the calendar follow the seasons or moon phases. Lunisolar calendars may require intercalations of both days and months.


The minute is a unit of time or angle. As a unit of time, the minute is most of times equal to ​1⁄60 (the first sexagesimal fraction) of an hour, or 60 seconds. In the UTC time standard, a minute on rare occasions has 61 seconds, a consequence of leap seconds (there is a provision to insert a negative leap second, which would result in a 59-second minute, but this has never happened in more than 40 years under this system). As a unit of angle, the minute of arc is equal to ​1⁄60 of a degree, or 60 seconds (of arc). Although not an SI unit for either time or angle, the minute is accepted for use with SI units for both. The SI symbols for minute or minutes are min for time measurement, and the prime symbol after a number, e.g. 5′, for angle measurement. The prime is also sometimes used informally to denote minutes of time.

New Earth Time

New Earth Time (or NET) is an alternative naming system for measuring the time of day. In NET the day is split into 360 NET degrees, each NET degree is split into 60 NET minutes and each NET minute is split into 60 NET seconds. One NET degree is therefore equivalent to four standard minutes, and one standard hour is equivalent to 15 NET degrees.

NET is equivalent to the UTC read from a 24-hour analog clock as the clockwise angle past midnight of the hour hand. For example, noon is 180°0'0" NET and at that time the hour hand is pointing straight down forming a 180° angle when measured from the top, at midnight. A full circle is 360 degrees and one NET day.


The past is the set of all events that occurred before a given point in time. The past is contrasted with and defined by the present and the future. The concept of the past is derived from the linear fashion in which human observers experience time, and is accessed through memory and recollection. In addition, human beings have recorded the past since the advent of written language. The first known use of the word "past" was in the fourteenth century; it developed as the past participle of the middle english verb passen meaning "to pass."

Planck time

In quantum mechanics, the Planck time (tP) is the unit of time in the system of natural units known as Planck units. A Planck time unit is the time required for light to travel a distance of 1 Planck length in a vacuum, which is a time interval of approximately 5.39 × 10 −44 s. The unit is named after Max Planck, who was the first to propose it.

The Planck time is defined as:


ħ = ​h2π is the reduced Planck constant (sometimes h is used instead of ħ in the definition)
G = gravitational constant
c = speed of light in vacuum

Using the known values of the constants, the approximate equivalent value in terms of the SI unit, the second, is

where the two digits between parentheses denote the standard error of the approximated value.

Time geography

Time geography or time-space geography is an evolving transdisciplinary perspective on spatial and temporal processes and events such as social interaction, ecological interaction, social and environmental change, and biographies of individuals. Time geography "is not a subject area per se", but rather an integrative ontological framework and visual language in which space and time are basic dimensions of analysis of dynamic processes. Time geography was originally developed by human geographers, but today it is applied in multiple fields related to transportation, regional planning, geography, anthropology, time-use research, ecology, environmental science, and public health. According to Swedish geographer Bo Lenntorp: "It is a basic approach, and every researcher can connect it to theoretical considerations in her or his own way."


A timeline is a display of a list of events in chronological order. It is typically a graphic design showing a long bar labelled with dates paralleling it, and usually contemporaneous events; a Gantt chart is a form of timeline used in project management.

Timelines can use any suitable scale representing time, suiting the subject and data; many use a linear scale, in which a unit of distance is equal to a set amount of time. This timescale is dependent on the events in the timeline. A timeline of evolution can be over millions of years, whereas a timeline for the day of the September 11 attacks can take place over minutes, and that of an explosion over milliseconds. While many timelines use a linear timescale -- especially where very large or small timespans are relevant -- logarithmic timelines entail a logarithmic scale of time; some "hurry up and wait" chronologies are depicted with zoom lens metaphors.

Tomorrow (time)

Tomorrow is a temporal construct of the relative future; literally of the day after the current day (today), or figuratively of future periods or times. Tomorrow is usually considered just beyond the present and counter to yesterday. It is important in time perception because it is the first direction the arrow of time takes humans on Earth.

UTC offset

The UTC offset is the difference in hours and minutes from Coordinated Universal Time (UTC) for a particular place and date. It is generally shown in the format ±[hh]:[mm], ±[hh][mm], or ±[hh]. So if the time being described is one hour ahead of UTC (such as the time in Berlin during the winter), the UTC offset would be "+01:00", "+0100", or simply "+01".

Every inhabited place in the world has a UTC offset that is a multiple of 15 minutes, and the majority of offsets (as well as all nautical time zones) are measured in whole hours.

UTC is the equivalent to GMT.


YVTO is the callsign of the official time signal from the Juan Manuel Cagigal Naval Observatory in Caracas, Venezuela. The content of YVTO's signal, which is a continuous 1 kW amplitude modulated carrier wave at 5.000 MHz, is much simpler than that broadcast by some of the other time signal stations around the world, such as WWV.

The methods of time transmission from YVTO are very limited. The broadcast employs no form of digital time code. The time of day is given in Venezuelan Standard Time (VET), and is only sent using Spanish language voice announcements. YVTO also transmits 100 ms-long beeps of 1000 Hz every second, except for thirty seconds past the minute. The top of the minute is marked by a 0.5 second 800 Hz tone.The station previously broadcast on 6,100 MHz but appears to have changed to the current frequency by 1990.

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