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Technical Note


Survey methodology

   Data collection for the American Time Use Survey (ATUS) began in
January 2003.  Sample cases for the survey are selected monthly and
interviews are conducted continuously throughout the year.  In 2007,
approximately 12,250 individuals were interviewed.  Estimates are
released annually.

   ATUS sample households are chosen from the households that com-
pleted their eighth (final) interview for the Current Population
Survey (CPS), the nation’s monthly household labor force survey.
ATUS sample households are selected to ensure that estimates will
be nationally representative.

   One individual age 15 or over is randomly chosen from each sam-
pled household.  This "designated person" is interviewed by tele-
phone once about his or her activities on the day before the inter-
view--the "diary day."

   All ATUS interviews are conducted using Computer Assisted Tele-
phone Interviewing.  Procedures are in place to collect information
from the small number of households that did not provide a telephone
number during the CPS interview.

   ATUS designated persons are preassigned a day of the week about
which to report.  Preassignment is designed to reduce variability in
response rates across the week and to allow oversampling of weekend
days so that accurate weekend day measures can be developed.  Inter-
views occur on the day following the assigned day.  For example, a
person assigned to report about a Monday would be contacted on the
following Tuesday.  Ten percent of designated persons are assigned
to report about each of the five weekdays.  Twenty-five percent are
assigned to report about each weekend day.  Households are called
for up to 8 consecutive weeks (for example, 8 Tuesdays) in order to
secure an interview.

About the questionnaire

   In the time diary portion of the ATUS interview, survey respondents
sequentially report activities they did between 4 a.m. on the day be-
fore the interview ("yesterday") until 4 a.m. on the day of the inter-
view.  For each activity, respondents are asked how long the activity
lasted.  For activities other than personal care activities (such as
sleeping and grooming), interviewers also ask respondents where they
were.  And for activities other than personal care and work, they are
asked who was in the room with them (if at home) or who accompanied
them (if away from home).  If respondents report doing more than one
activity at a time, they are asked to identify which one was the "main"
(primary) activity. If none can be identified, then the interviewer re-
cords the first activity mentioned.  After completing the time diary,
interviewers ask respondents additional questions to clearly identify
work, volunteering, and secondary childcare activities.  Secondary
childcare is defined as having a child under age 13 in one’s care while
doing other activities.


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   In addition, the ATUS includes an update of the household composition
information from the last CPS interview (2 to 5 months prior to the ATUS
interview) and the employment status information of the respondent and
his or her spouse or unmarried partner.  For respondents who became em-
ployed or changed jobs between the last CPS interview and the ATUS inter-
view, information also is collected on industry, occupation, class of
worker, and earnings.  For those who are unemployed and/or on layoff, CPS
questions on job search activities are asked.  Those who report being on
layoff are asked if or when they expect to be recalled to work.  Finally,
a question about current school enrollment status is asked of all respon-
dents ages 15 to 49.

   After completing the interview, primary activity descriptions are as-
signed a single 6-digit code using the ATUS Coding Lexicon.  The 3-tier
coding system consists of 17 major activity categories, each with multi-
ple second- and third-tier subcategories.  These coding lexicon categor-
ies are then combined into composite categories for publication, such as
in this news release.  Descriptions of categories shown in this release
can be found in the Major activity category definitions section of this 
Technical Note.  The 2007 ATUS Coding Lexicon can be accessed at http://
www.bls.gov/tus/lexicons.htm.

Concepts and definitions

   Average day.  The average day measure reflects an average distribution
across all persons in the reference population and all days of the week.
Average day measures for the entire population provide a mechanism for
seeing the overall distribution of time allocation for society as a whole.
The ATUS collects data about daily activities from all segments of the
population age 15 and over, including persons who are employed and not em-
ployed.  Activity profiles differ based upon age, employment status, gender,
and other characteristics.  On an average day in 2007, persons in the U.S.
age 15 and over worked for 3.8 hours, slept about 8.6 hours, spent 5.1 hours
doing leisure and sports activities, and spent 1.8 hours doing household ac-
tivities.  The remaining 4.7 hours were spent doing a variety of other activ-
ities, including eating and drinking, attending school, and shopping.  (See
table 1.) By comparison, an average weekday for persons employed full time
on days that they worked included 9.1 hours working, 7.6 hours sleeping, 3.0
hours doing leisure and sports activities, and 0.9 hour doing household activ-
ities.  The remaining 3.4 hours were spent in other activities, such as those
described above.  (These estimates include related travel time.)

   Many activities typically are not done on a daily basis, and some activ-
ities only are done by a subset of the population.  For example, only 46 per-
cent of all persons age 15 years and over worked on an average day in 2007
because some were not employed and those who were employed did not work every
day.  (See table 1.)

   Average hours per day.  The average number of hours spent in a 24-hour day
(between 4 a.m. on the diary day and 4 a.m. on the interview day) doing a spe-
cified activity.

   --Average hours per day, population.  The average number of hours per day
     is computed using all responses from a given population, including those
     of respondents who did not do a particular activity on their diary day.
     These estimates reflect how many population members engaged in an activ-
     ity and the amount of time they spent doing it.

   --Average hours per day, persons who did the activity.  The average number
     of hours per day is computed using only responses from those who engaged
     in a particular activity on their diary day.

   Diary day.  The diary day is the day about which the respondent reports.
For example, the diary day of a respondent interviewed on Tuesday is Monday.


                                   - 6 -

Earnings

   --Usual weekly earnings.  Data represent the earnings of full-time wage
     and salary workers before taxes and other deductions and include any
     overtime pay, commissions, or tips usually received (at the main job
     in the case of multiple jobholders).  Usual weekly earnings are only
     updated in ATUS for about a third of employed respondents--if the
     respondent changed jobs or employment status or if the CPS weekly
     earnings value was imputed.  This means that the earnings information
     could be out of date because the CPS interview was done 2 to 5 months
     prior to the ATUS interview.  Respondents are asked to identify the
     easiest way for them to report earnings (hourly, weekly, biweekly,
     twice monthly, annually, or other) and how much they usually earn in
     the reported time period.  Earnings reported on a basis other than
     weekly are converted to a weekly equivalent.  The term "usual" is as
     perceived by the respondent.  If the respondent asks for a definition
     of usual, interviewers are instructed to define the term as more than
     half the weeks worked during the past 4 or 5 months.

   --Weekly earnings ranges.  The ranges used represent approximately 25 per-
     cent of full-time wage and salary workers.  For example, 25 percent of
     full-time wage and salary workers had weekly earnings of $480 or less.
     These dollar values vary from year to year.

Employment status

   --Employed.  All persons who, at any time during the 7 days prior to the
     interview:

     1)  Did any work at all as paid employees; worked in their own business,
     profession, or on their own farm; or usually worked 15 hours or more as
     unpaid workers in a family-operated enterprise; or

     2)  Were not working but had jobs or businesses from which they were tem-
     porarily absent due to illness, bad weather, vacation, childcare problems,
     labor-management disputes, maternity or paternity leave, job training, or
     other family or personal reasons, whether or not they were paid for the
     time off or were seeking other jobs.

   --Employed full time.  Full-time workers are those who usually worked 35
     hours or more per week at all jobs combined.

   --Employed part time.  Part-time workers are those who usually worked fewer
     than 35 hours per week at all jobs combined.

   --Not employed.  Persons are not employed if they do not meet the conditions
     for employment.  The not employed include those classified as unemployed as
     well as those classified as not in the labor force (using CPS definitions).

   The numbers of employed and not employed persons in this report do not corre-
spond to published totals from the CPS for several reasons.  First, the reference
population for the ATUS is age 15 years and over, whereas it is age 16 years and
over for the CPS.  Second, ATUS data are collected continuously, the employment
reference period being the 7 days prior to the interview.  By contrast, CPS data
are usually collected during the week including the 19th of the month and refer
to employment during the week containing the 12th of the month.  Finally, the
CPS accepts answers from household members about other household members whereas
such proxy responses are not allowed in the ATUS.  One consequence of the differ-
ence in proxy reporting is that a significantly higher proportion of teenagers
report employment in the ATUS than in the CPS.  While the information on employ-
ment from the ATUS is useful for assessing work in the context of other daily
activities, the employment data are not intended for analysis of current employ-
ment trends.  Compared with the CPS and other estimates of employment, the ATUS
estimates are based on a much smaller sample and are only available with a sub-
stantial lag since ATUS data and estimates are published during the year fol-
lowing data collection.


                                   - 7 -

   Household children.  Household children are children under age 18 residing
in the household of the ATUS respondent.  The children may be related to the re-
spondent (such as his or her own children, grandchildren, nieces or nephews, or
brothers or sisters) or not related (such as foster children or children of room-
mates).  For secondary childcare calculations, respondents are asked separately
about care for own and nonown household children under age 13.

   Primary activity.  A primary activity is the main activity a respondent was
doing at a specified time.  With the exception of secondary childcare in table 10,
the estimates presented in this release reflect time spent in primary activities
only.

   Secondary activities.  A secondary (or simultaneous) activity is an activity
done at the same time as a primary activity.  With the exception of the care of
children under age 13, information on secondary activities is not systematically
collected in the ATUS.

   Secondary childcare.  Secondary childcare is care for children under age 13
that is done while doing an activity other than primary childcare, such as cooking
dinner.  Secondary childcare estimates are derived by summing the durations of ac-
tivities during which respondents had a household child or their own nonhousehold
child under age 13 in their care while doing activities other than primary child-
care.  It is restricted to times the respondent was awake.  Secondary childcare
time for household children is further restricted to the time between when the
first household child under age 13 woke up and the last household child under 
age 13 went to bed.  If respondents report providing both primary and secondary
care at the same time, the time is attributed to primary care only.

   Weekday, weekend, and holiday estimates.  Estimates for weekdays are an average
of reports about Monday through Friday.  Estimates for weekend days and holidays
are an average of reports about Saturdays, Sundays, and the following holidays:
New Year’s Day, Easter, Memorial Day, the Fourth of July, Labor Day, Thanksgiving
Day, and Christmas Day.  In 2007, the telephone call center was closed the day
after New Year’s Day, so data were not collected about this holiday.

Major activity category definitions

   The following definitions describe the activity categories shown in this report.
All major time-use categories in the tables include related travel time and waiting
time.  For example, time spent "driving to the stadium" and time spent "waiting to
get into the stadium to play ball" are included in Leisure and sports.

   Personal care activities.  Personal care activities include sleeping, grooming
(such as bathing or dressing), health-related self-care, and personal or private
activities.  Receiving unpaid personal care from others (for example, "my sister
put polish on my nails") also is captured in this category.  Respondents are not
asked who they were with or where they were for personal care activities, as such
information can be sensitive.

   Eating and drinking.  All time spent eating or drinking (except eating and
drinking done as part of a work or volunteer activity), whether alone, with
others, at home, at a place of purchase, or somewhere else, is classified here.
Time spent purchasing or talking related to purchasing meals, snacks, or bever-
ages is not counted as part of this category; time spent doing these activities
is counted in Purchasing goods and services.

   Household activities.  Household activities are those done by persons to main-
tain their households.  These include housework; cooking; lawn and garden care;
pet care; vehicle maintenance and repair; home maintenance, repair, decoration,
and renovation; and household management and organizational activities (such as
filling out paperwork, balancing a checkbook, or planning a party).  Food pre-
paration, whether or not reported as done specifically for another household
member, is always classified as a household activity, unless it was done as a
volunteer, work, or income-generating activity.  For example, "making break-
fast for my son" is coded as a household activity, not as childcare.


                                        - 8 -

   Purchasing goods and services.  This category includes purchases of consumer
goods, professional and personal care services, household services, and govern-
ment services.  Consumer purchases include most purchases and rentals of consumer
goods, regardless of the mode or place of purchase or rental (in person, via tele-
phone, over the Internet, at home, or in a store).  Gasoline, grocery, other food
purchases, and all other shopping are further broken out in subcategories.

   Time spent obtaining, receiving, and purchasing professional and personal care
services provided by someone else also is classified in this category.  Profes-
sional services include childcare, financial services and banking, legal services,
medical and adult care services, real estate services, and veterinary services.
Personal care services include day spas, hair salons and barbershops, nail salons,
and tanning salons.  Activities classified here include time spent paying, meeting
with, or talking to service providers, as well as time spent receiving the service
or waiting to receive the service.

   Time spent arranging for and purchasing household services provided by someone
else also is classified here.  Household services include housecleaning; cooking;
lawn care and landscaping; pet care; tailoring, laundering, and dry cleaning; ve-
hicle maintenance and repairs; and home repairs, maintenance, and construction.

   This category also captures the time spent obtaining government services--such
as applying for food stamps--and purchasing government-required licenses or paying
fines or fees.

   Caring for and helping household members.  Time spent doing activities to care
for or help any child (under age 18) or adult in the household, regardless of re-
lationship to the respondent or the physical or mental health status of the person
being helped, is classified here.  Caring for and helping activities for household
children and adults are coded separately in subcategories.

   Primary childcare activities include time spent providing physical care; playing
with children; reading to children; assistance with homework; attending children’s
events; taking care of children’s health needs; and dropping off, picking up, and
waiting for children.  Passive childcare done as a primary activity (such as "keeping
an eye on my son while he swam in the pool") also is included.  A child’s presence
during the activity is not enough in itself to classify the activity as childcare.
For example, "watching television with my child" is coded as a leisure activity, not
as childcare.

   Secondary childcare occurs when persons have a child under age 13 "in their care"
while doing activities other than primary childcare.  For a complete definition, see
the Concepts and definitions section of this Technical Note.

   Caring for and helping household members also includes a range of activities done
to benefit adult members of households, such as providing physical and medical care
or obtaining medical services.  Doing something as a favor for or helping another
household adult does not automatically result in classification as a helping activ-
ity.  For example, a report of "helping my spouse cook dinner" is considered a
household activity (food preparation), not a helping activity, because cooking din-
ner benefits the household as a whole.  By contrast, doing paperwork for another
person usually benefits the individual, so a report of "filling out an insurance
application for my spouse" is considered a helping activity.

   Caring for and helping nonhousehold members.  Caring for and helping nonhouse-
hold members includes activities persons do to care for or help those--either chil-
dren (under age 18) or adults--who do not live with them.  When done for or through an
organization, time spent helping nonhousehold members is classified as volunteering,
rather than as helping nonhousehold members.  Care of nonhousehold children, even when
done as a favor or helping activity for another adult, is always classified as caring
for and helping nonhousehold children, not as helping another adult.


                                   - 9 -

   Working and work-related activities.  This category includes time spent working,
doing activities as part of one’s job, engaging in income-generating activities (not
as part of one’s job), and job search activities.  "Working" includes hours spent
doing the specific tasks required of one’s main or other job, regardless of location
or time of day.  "Work-related activities" include activities that are not obviously
work but are done as part of one’s job, such as having a business lunch or playing
golf with clients. "Other income-generating activities" are those done "on the side"
or under informal arrangement and are not part of a regular job.  Such activities
might include selling homemade crafts, babysitting, maintaining a rental property,
or having a yard sale.  These activities are those that persons "are paid for or
will be paid for."

   Travel time related to working and work-related activities includes time spent
traveling to and from work, as well as time spent traveling for work-related, in-
come-generating, and job search activities.

   Educational activities.  Educational activities include taking classes (including
Internet and other distance-learning courses) for a degree as well as for personal in-
terest; doing research and homework; and taking care of administrative tasks related
to education, such as registering for classes or obtaining a school ID.  For high
school students, before- and after-school extracurricular activities (except sports)
also are classified as educational activities.  Educational activities do not include
time spent for classes or training received as part of a job.  Time spent helping
others with their education-related activities is classified in the Caring for and
helping categories.

   Organizational, civic, and religious activities.  This category captures time
spent volunteering for or through an organization, performing civic obligations, and
participating in religious and spiritual activities.  Civic obligations include gov-
ernment-required duties, such as serving jury duty or appearing in court, and activi-
ties that assist or influence government processes, such as voting or attending town
hall meetings. Religious activities include those normally associated with membership
in or identification with specific religions or denominations, such as attending reli-
gious services; participating in choirs, youth groups, orchestras, or unpaid teaching
(unless identified as volunteer activities); and engaging in personal religious pract-
ices, such as praying.

   Leisure and sports.  The leisure and sports category includes sports, exercise, and
recreation; socializing and communicating; and other leisure activities.  Sports, ex-
ercise, and recreation activities include participating in--as well as attending or 
watching--sports, exercise and recreational activities.  Recreational activities are 
leisure activities that are active in nature, such as yard games like croquet or 
horseshoes.  Socializing and communicating includes face-to-face social communication 
and hosting or attending social functions.  Leisure activities include watching tele-
vision; reading; relaxing or thinking; playing computer, board, or card games; using 
a computer or the Internet for personal interest; playing or listening to music; and 
other activities, such as attending arts, cultural, and entertainment events.

   Telephone calls, mail, and e-mail.  This category captures telephone communication
and handling household or personal mail or e-mail.  Telephone and Internet purchases
are classified in Purchasing goods and services.  Telephone calls, mail, or e-mail
identified as related to work or volunteering are classified as work or volunteering.

   Other activities, not elsewhere classified.  This residual category includes secur-
ity procedures related to traveling, traveling not associated with a specific activity
category, ambiguous activities that could not be coded, and missing activities.  Mis-
sing activities result when respondents did not remember what they did for a period of
time, or when they considered an activity too private or personal to report.

Processing and estimation

   After ATUS data are collected, they go through an editing and imputation procedure.
Responses to CPS questions that are re-asked in the ATUS go through the regular CPS
edit and imputation procedures.  Some item nonresponses for questions unique to the
ATUS (such as where an activity took place or how much time was spent doing secondary
childcare) also are imputed.  Missing activities and missing values for who was present
during an activity are never imputed.


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   ATUS records are weighted to reduce bias in the estimates due to differences in
sampling and response rates across subpopulations and days of the week.  Specifically,
the data are weighted to ensure the following:

   --Weekdays represent about 5/7 of the weighted data, and weekend days each represent
     about 1/7 of the weighted data for the population as a whole.  The actual propor-
     tions depend on the number of weekdays and weekend days in a given quarter.

   --The sum of the weights is equal to the number of person-days in the quarter for
     the population as a whole and for selected subpopulations.

Reliability of the estimates

   Statistics based on the ATUS are subject to both sampling and nonsampling error.
When a sample, rather than the entire population, is surveyed, there is a chance that
the sample estimates may differ from the "true" population values they represent.  The
exact difference, or sampling error, varies depending on the particular sample selected,
and this variability is measured by the standard error of the estimate.  There is about
a 90-percent chance, or level of confidence, that an estimate based on a sample will 
differ by no more than 1.6 standard errors from the "true" population value because
of sampling error.  BLS analyses are generally conducted at the 90-percent level of
confidence.

   The ATUS data also are affected by nonsampling error. Nonsampling error can occur
for many reasons, including the failure to sample a segment of the population, inabil-
ity to obtain information for all respondents in the sample, inability or unwilling-
ess of respondents to provide correct information, and errors made in the collection
or processing of the data.  Errors also could occur if nonresponse is correlated with
time use.