BLS WORKING PAPERS 

 

U.S. Department of Labor 

U.S. Bureau of Labor Statistics 

Office of Employment and Unemployment Statistics 

How Does Employment Affect the Timing of Time with Children? 

Jay Stewart, U.S. Bureau of Labor Statistics 

Mary Dorinda Allard, Program Director, ATUS

Working Paper 419

May 2008

All views expressed in this paper are those of the authors and do not necessarily reflect the views or policies of the 

U.S. Bureau of Labor Statistics. 
How Does Employment Affect the Timing of Time with Children? 

 May 2008 

Jay Stewart (corresponding author) 

U.S. Bureau of Labor Statistics 

2 Massachusetts Ave., NE 

Washington, DC 20212 

USA 

Stewart.Jay@bls.gov

(202) 691-7376 

Mary Dorinda Allard 

U.S. Bureau of Labor Statistics 

2 Massachusetts Ave., NE 

Washington, DC 20212 

USA 

Allard.Dorinda@bls.gov

(202) 691-6470 

Any views expressed are ours and do not necessarily reflect those of the Bureau of Labor 

Statistics. We thank Bob Drago, Harley Frazis, Irina Paley, and participants in the IZA 

Topic Week on Nonmarket Time in Economics for their helpful comments and 

suggestions. 
Abstract 

A large body of literature has examined the effect of parental employment--primarily 

maternal employment--on the amount of time spent with children and in childcare activities, and 

it is well documented that employed parents spend less time with their children than 

nonemployed parents. But not all time is equal. Research on circadian rhythms suggests that 

children’s ability to benefit from parents’ enriching childcare activities, such as reading to and 

playing with their children, varies by time of day. Thus, we would expect parents to engage in 

these enriching activities at times of day when it is the most valuable to their children. If 

employment causes parents to shift their childcare activities away from times when it is the most 

valuable, then differences in the amount of time that employed and nonemployed parents spend 

in childcare underestimate the effect of employment on parents’ quality-adjusted time with their 

children. 

In this study, we examine whether employment results in parents shifting the time spent 

engaging in childcare activities to times that may be less productive. We develop a simple 

model of timing that predicts that parents will spend more time with their children when it is 

most productive. We then use data from the American Time Use Survey to compare workdays 

to nonwork days, and find that employment significantly affects the timing of enriching childcare 

activities for both mothers and fathers who are employed full time. In particular, these parents 

shift enriching childcare activities into the evening hours. In contrast, part-time employment has 

a much smaller effect on when mothers spent time with their children. Thus, part-time 

employment not only allows mothers to spend more time with their children compared to fulltime employment, it also allows them to spend that time when it may be the most beneficial and 

enjoyable. 
Introduction 

Parental time spent in enriching childcare activities, such as playing with and reading to 

children, is arguably one of the most important parental inputs into child development. A large 

body of literature has examined the effect of employment on the amount of time that parents 

spend providing childcare,1

 but there has been almost no research on when that care is provided.2 

The timing of childcare matters because not all time is equally valuable; for example, time spent 

in enriching childcare activities is likely to be more beneficial to the children and more enjoyable 

to parents at times when children are more receptive to learning and parents are not tired. If it is 

the amount of quality-adjusted time with children that matters and employment causes parents to 

shift enriching childcare to “less-productive” times of day, then looking only at the amount of 

time in enriching childcare understates the full impact of employment on parental time with 

children. 

The large literature on circadian rhythms examines how biological functions vary over 

the course of the day.3

 One facet of this research focuses on individuals’ preferences for certain 

times of day, with individuals being classified as preferring either mornings or evenings. These 

studies are based on the Morningness-Eveningness Questionnaire (MEQ), which is designed to 

assess the subjects’ preferences.4

 Most of the research has focused on teenagers and young 

adults, and older individuals. Teens and young adults generally prefer afternoons and evenings, 

while older individuals tend to prefer mornings. Other studies have shown that performance on 

 

1

 For example, see Bianchi (2000, 2006) and Bianchi, Robinson, and Milkie (2006). 2

 Craig (2006) presents some evidence that employed mothers are less likely to spend time with their children in the 

morning and the afternoon. 

3

 This discussion is based on Hasher, Goldstein, and May (2005), which contains a nice summary of the relevant 

research on this topic. 

4

 The MEQ asks respondents about preferred times for doing certain types of activities, as well as preferred times for 

waking up and going to sleep. 
- 2 -

complex tasks was better at preferred times of day, whereas performance on routine problemsolving tasks is invariant to the time of day. 

There is less research available on the time-of-day preferences of young children. Two 

studies have examined the morningness/eveningness of 8-16 year olds (Kim, et al 2002) and 2-6 

year olds (Wickersham 2006). In the latter study, the MEQ was adapted so that parents could 

answer for their children. The Kim, et al study found that younger children preferred the 

mornings, while older children preferred afternoons and evenings. The crossover point for this 

change is at about age 13. The Wickersham study found that preschool-age children preferred 

mornings, and that the preference was quite strong in two- and three-year-olds. If young 

children also perform better on complex tasks at their preferred time of day, then we might 

expect enriching care to be more valuable and thus more “productive” in the morning than in the 

afternoon and evening. 

If time of day affects the benefits that parents receive from parent-child interactions, then 

we would expect parents to have preferences about when they spend time with their children.5

 

Our main concern is enriching activities because they are an important input to child 

development, the value of time spent in these activities is likely to depend on time of day, and 

they can be easily shifted to other times. We seek to determine whether employed parents shift 

their childcare activities from more-productive times to less-productive times, thus reducing the 

value of parental time with children. 

We begin by developing a simple model of timing. The model predicts that, all else 

equal, parents will spend more time with their children at times when the time is most 

productive. It is important to note that productivity depends on the parents’ time-of-day 

 

5

 Parents’ preferences will depend on the weight attached to their eveningness preference and the morningness 

preference of their children. Given that the enriching care activities are likely to be complicated for young children 

and relatively routine for their parents, we would expect mornings to be the best time for these interactions. 
- 3 -

preferences as well as those of the children. The productivity of time spent in other activities can 

vary by time of day as well. If time spent in work activities is more productive during normal 

working hours, then we would expect parents to shift time with children away from workdays 

and away from normal working hours on workdays. If time with children is also more 

productive during normal work hours compared to evening hours, then we would expect to see 

parents spend more time with their children during these hours on their nonwork days. On the 

other hand if time with children is most productive at times other than normal working hours, 

then employment should not affect when parents spend time with their children and the pattern 

of when parents spend time with their children should be the same time on workdays and 

nonwork days. 

A Simple Model of Timing 

 In this section we present a simple economic model that shows how variation in the 

productivity of time spent in different activities over the course of the day affects when people 

choose to engage in those activities.6

 For convenience and ease of exposition we assume that 

individuals optimize in two stages. In the first stage, the individual maximizes utility and 

determines the optimal amount of time to spend in each activity during a given period of time, 

such as a day. In the second stage, the individual determines how that time spent in each activity 

is distributed over the sub-periods, such as morning or evening.7

 For simplicity, we assume that 

there are two sub-periods and two activities. 

 

6

 There is relatively little research on the timing of activities. Our model is most similar to that in a study examining 

the effect of weather on the timing of work and leisure activities (Conolly 2008). Two other studies examine the 

timing of work activities (Hamermesh, Knowles, and Pocock 2006) and the coordination of husbands’ and wives’ 

time with children (Paley 2006). An early paper by Winston (1982) presents a theoretical model of timing. 7

 Technically, it would be more realistic to solve the utility maximization problem in one stage with the time spent in 

each activity at each time as an argument in the utility function. But it is easier to see the intuition in the two-stage 

model. 
- 4 -

First Stage Optimization: Individuals receive utility from time spent in enriching 

childcare, A, and all other activities, X, which include leisure, household work, and working for 

pay.8

 The productivity of time spent in each of these activities is given by the functions Γ(γ) for 

activity A and Θ(θ) for X, where the arguments γ and θ are vectors of productivities for the subperiods and Γi, Θi >0 for i = 1,2. Each parent solves the following first-stage optimization 

program: 

Max A,X U( ) Γ() () γ A,Θ θ X s.t. A+ X = 2T , 

where T is the amount of time in each sub-period. The solution to this program is 

straightforward and the optimal values of A and X will be denoted as A* and X*. 

 Second Stage Optimization: Parents distribute the time spent in the two activities to the 

two time periods based on the productivity of the activities in the sub-periods. Again, keep in 

mind that the productivity of time spent in childcare depends on the parent’s and children’s timeof-day preferences, as well as any interaction effects. Letting ai and xi denote the time spent in 

childcare and in other activities, the maximization program can be written as: 

( ) ( ) ( ) ( ) Max 1 1 2 2 1 1 2 2 u = γ f a + γ f a +θ g x +θ g x

a x T

a x T

x x X

a a A

+ =

+ =

+ =

+ =

2 2

1 1

1 2

1 2

*

s.t. *

Substituting in the last two constraints, the Lagrangian is: 

 

8

 The utility from X therefore includes utility derived from goods purchased from labor market earnings as well as 

the utility of leisure and the utility derived from household production. A more traditional model that includes 

market work and leisure as separate activities, includes consumption of market goods, and explicitly models 

household production would be more complicated but the important results would not change. 
- 5 -

() ( ) ( ) ( )

( ) * ( ) * [ ] 2 , 1 2 1 2

1 1 2 2 1 1 2 2

A a a X T a a

f a f a g T a g T a

A − − + X − − −

= + + − + − +

λ λ

L γ γ θ θ

and the first order conditions with respect to a1 and a2 are: 

(1) 

() ( )

() ( ) 0,

0

2 2 2 2

1 1 1 1

2

1

= ′ − ′ − + − =

= ′ − ′ − + − =

a X A

a X A

f a g T a

f a g T a

γ θ λ λ

γ θ λ λ

L

L

which can be rewritten as: 

(2) 

() ( )

() ( ) A X

A X

f a g T a

f a g T a

γ θ λ λ

γ θ λ λ

′ = ′ − + −

′ = ′ − + −

2 2 2 2

1 1 1 1

Combining the equations in (2) yields the following equilibrium condition: 

 (2′) () ( ) ( ) ( ) 1 1 1 1 2 2 2 2 γ f ′ a −θ g′ T − a = γ f ′ a −θ g′ T − a

which states that the individual equates the difference between the marginal utilities of the two 

activities across the two time periods.9

 We know from (1) that this difference is (λA − λX). 

Figure 1 graphs the equations in (2) and illustrates the equilibrium. 

 For our question, we are interested in how differences in productivity affect the amount 

of time spent in activity A in the two sub-periods. An increase in γ1 affects a1 and a2 directly 

though changes in the relative productivities of A and X in sub-periods 1 and 2, and indirectly 

through a change in A*. The former effect is akin to a substitution effect, while the latter is akin 

to a scale effect. 

 

9

 The inequality of the marginal products is an artifact of the two-stage optimization program and the adding-up 

constraint in the second stage. 
- 6 -

The substitution effect can be seen by holding A* (and hence X*) constant and totally 

differentiating the equilibrium condition for the second stage in equation (2′) with respect to γ1

using the implicit function rule, yielding the following: 

(3) ( ) () () () () 0 *

2 2

*

2 2

*

1 1

*

1 1

*

1

1 0

*

1

*

> ′′ + ′′ + ′′ + ′′

− ′ =

= f a g x f a g x

f a

d

da

dA γ γ θ γ θ . 

Thus an increase in the productivity of activity A in sub-period 1 increases the time spent on 

activity A in sub-period 1 holding the total amount of time spent on activity A constant.10 In 

Figure 2, this is illustrated as an upward shift in the ( ) 1 1 γ f ′ a curve. The ( ) A X θ1g′ T − a1 + λ − λ

and ( ) A X θ 2 g′ T − a2 + λ − λ ( )1 θg′ x curves also shift upward, because the first constraint becomes 

more binding (it is easily shown that ∂λA/∂γ1>0), such that Δa1 = −Δa2. Similarly, 

(4) ( ) () () () () 0 *

2 2

*

2 2

*

1 1

*

1 1

*

1

1 0

*

1

*

< ′′ + ′′ + ′′ + ′′

− ′ =

= f a g x f a g x

g x

d

da

dA θ γ θ γ θ , 

so that an increase in the productivity of other activities decreases the time spent in A in subperiod 1. 

 The direction of the scale effect is ambiguous. Totally differentiating the first-stage 

equilibrium condition yields: 

[ () () ( ) ( ) ( )]

() () () γ γ θ

γ γ γ γ θ

Γ − Γ Θ

− Γ Γ + Γ − Γ Θ =

21

2

11

*

1 1 21 1

*

11 1

1

*

U U

U A U U A

d

dA

γ , 

which reduces to: 

 

10 If the daily production function is specified as ( ) 1a1 f γ instead of ( ) 1 a1 γ f , then 1

*

1 da dγ is positive as long as the 

elasticity of marginal product with respect to quality-adjusted time is greater than −1. If the marginal product 

function is elastic, then the amount of quality-adjusted time increases, but actual time decreases. The result in 

equation (4) also depends on the assumption that utility in the second stage is additively separable across activities 

and time periods. However, this assumption seems reasonable over short period of time such as a day or so. 
- 7 -

( )

( ) ⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ Γ ⋅ −

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ − Γ ⋅ − +

=

Γ Θ

Γ Θ

U A U X

U A U X

X

A

X

A A

d

dA

* ,

*

,

* ,

*

,

*

1

1

*

1 1

1 1 1

δ δ

δ δ

γ γ

γ

<

=

> 0, 

where , 0 1 δ U ΓA < is the own elasticity of the marginal utility with respect to quality-adjusted time 

in A (which equals Γ·A) and δ U1 ,ΘX is the elasticity with respect to quality-adjusted time in X 

(which equals Θ·X). If 1 0 * ,

*

, 1 1 <⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛ − < U ΓA − U ΘX X

A δ δ then 0

1

*

>

dγ

dA . If A* is small relative to 

X*, as would be the case for enriching childcare activities, then 0

1

*

>

dγ

dA if 1 , 0 1 − < δ U ΓA < . 

 The effect of employment on the timing of childcare can be seen by comparing work 

days and nonwork days. Workdays differ from nonwork days in that the productivity of “other 

activities,” which includes paid work, is higher. Because our main focus is on the timing of 

enriching childcare over the course of the day, we do not explicitly model the shifting of 

activities between days. However, it is relatively straightforward to extend our model to multiple 

days, and we will discuss between-day shifting on childcare in the context of the model. For 

simplicity, suppose that the productivity of childcare is higher in period 1 than in period 2 and 

that the productivity does not depend on whether the day in question is a workday 

( ) 1 1 2 2

N W N W γ = γ > γ = γ , where the W and N superscripts denote workdays and nonwork days. 

Other activities are assumed to have the same productivity in both periods on nonwork days and 

have higher productivity in period 1 on workdays ) ( 1 1 2 2

W N N W θ >θ =θ = θ . The higher 

productivity of other activities in period 1 reflects the higher productivity of work during normal 

work hours due to the coordination of work activities (see Hamermesh, Knowles, and Pocock 

2006). Thus, we would expect individuals to work more in period 1 on workdays. This has two 
- 8 -

implications for childcare. First, employed individuals will shift childcare activities from 

workdays to nonwork days. Second, and more importantly, childcare done on workdays will be 

shifted from period 1 to period 2. 

Data 

 We use pooled 2003-2006 data from the American Time Use Survey (ATUS).11 The 

ATUS is a time-diary survey that asks respondents to sequentially describe their activities, which 

are translated into over 400 detailed activity codes, during a 24-hour period that we refer to as 

the diary day.12 Twenty-six different activity codes describe childcare of household children, 

and for this analysis we defined three broad categories of childcare: routine care (such as feeding 

or bathing), enriching care (such as reading to or playing with children), and other childcare 

(such as travel). (See Appendix A for detailed definitions.) For each episode, the ATUS collects 

the start and stop times, who else was present, and where the respondent was. The ATUS also 

contains demographic information for all household members and labor force information 

(including labor force status and usual hours worked) for the respondent and the respondent’s 

spouse or unmarried partner. 

 The ATUS interviews one person per household and each respondent is interviewed only 

once about the day prior to the interview. Thus it is not possible to directly observe the shifting 

of activities between work and nonwork days. Instead, we compare employed parents who were 

interviewed about a workday to those who were interviewed about a nonwork day, keeping in 

 

11 A more complete description of the ATUS can be found in Hamermesh, Frazis, and Stewart (2005) and Frazis and 

Stewart (2007). 

12 If respondents report doing more than one thing at one time (such as cooking while talking to a child), only the 

activity reported as the primary (or “main”) activity is coded. However, traveling--even when done in conjunction 

with another activity, such as feeding a child--is always considered the primary activity. The diary day starts at 4am 

“yesterday” and ends at 4am “today.” 
- 9 -

mind that whether a given diary day is a work day or a nonwork day is exogenously determined 

because respondents are pre-assigned to be interviewed about a particular day of the week. 

 To isolate the effect of work-related constraints on when parents provide childcare, it is 

important to eliminate the effects of school on parental time with children.13 Therefore, we 

restricted our sample to parents aged 18 and older who have at least one pre-school age child 

(under age 5) living in the household.14 This leaves us with a sample size of 9,103. 

Approximately 50 percent of these parents also have children that are age 5 or older and so 

provide childcare to these children as well. For this reason, only childcare activities that were 

done when a child under age 5 was present are counted as childcare. 

Table 1 shows the average number of hours per day spent in childcare activities by 

employed and nonemployed parents. Employed mothers are divided into full-time and part-time 

workers. Fathers who work part time are excluded from the analysis due to the small sample 

size. Mothers spend considerably more time in childcare than fathers regardless of employment 

status. Nonemployed mothers spend more time in childcare (3.1 hours per day) than either parttime employed mothers (2.7 hours) or full-time employed mothers (2.1 hours). Nonemployed 

fathers spend more time in childcare activities than full-time employed fathers, but not as much 

as nonemployed mothers. 

Routine care accounts for most of the time spent in childcare. Enriching care accounts 

for about 33% of mothers’ childcare time and a little over 40% of fathers’ childcare time; there is 

little variation in these fractions by employment and full/part time status. Working fewer hours 

increases the amount of time spent on both routine and enriching care by about the same relative 

amount. 

 

13 Note that older children may also be present. 

14 “Parents” are those with biological children, stepchildren, or adopted children. 
- 10 -

Workdays vs. Nonwork Days 

Table 1 also shows how childcare is divided between workdays and nonwork days. 

Because parents working at home can provide significant amounts of childcare, workdays are 

defined as those days respondents reported working somewhere other than at home. Employed 

parents spend less time in childcare on workdays than on nonwork days. Somewhat surprisingly, 

the difference between workdays and nonwork days is greater for part-time employed mothers 

than it is for full-time employed mothers (about 70 minutes less per day vs. about 45 minutes 

less for full-time employed mothers). 

We can also see from Table 1 that employed parents spend more time in childcare 

activities on nonwork days than they do on workdays. Both mothers and fathers spend more time 

on routine care and enriching care on nonwork days compared to workdays. The two largest 

components of enriching care are playing with children and reading to children. Parents spend 

more time playing with children on nonwork days, but the amount of time parents spend reading 

to children—which is mostly done at night—is about the same on work and nonwork days. 

Other childcare, which includes transporting children, is also about the same on work and 

nonwork days. 

These findings are consistent with our prediction that parents will shift childcare time 

from work days to nonwork days (except for “other childcare” and “reading to children” as 

discussed previously). They are also consistent with the findings of Stafford and Yeung (2005) 

that children spend more time with their parents on weekend days than on weekdays. 

The Timing of Childcare 

 The timing of enriching childcare activities depends on the relative productivities of 

childcare and other activities at different times of the day. Given our assumption that the 
- 11 -

productivity of time spent in non-enriching childcare activities does not depend on time of day 

on nonwork days, the timing of enriching care on those days depends only on the productivity of 

enriching care at different times of day. 

Our empirical strategy is to compare the timing of childcare on workdays and nonwork 

days. Since we cannot observe the same person on both a workday and a nonwork day, there are 

two possible control groups for the nonwork days—nonemployed parents and employed parents 

on nonwork days. Using nonemployed persons as the control group is potentially problematic 

because the employment decision may be related to unobserved differences in productivity. For 

example, individuals whose childcare time is relatively productive in the evening may be more 

likely to be employed full time. If this is the case, we would expect these individuals to 

concentrate their childcare activities in the evening on their nonwork days as well. This leads us 

to use the nonwork days of the employed as the control group, which eliminates the endogeneity 

issue because the two comparison groups have exactly the same characteristics. The important 

thing to note is that parents were randomly assigned to days, so that whether a parent is observed 

on a workday or a nonwork day is exogenous. Thus the work-schedule effect is identified by 

comparing the timing of childcare of parents who were interviewed on a workday to those who 

were interviewed on a nonwork day.15 

 The research on circadian rhythms suggests that mornings may be the best time (from the 

child’s perspective) for enriching care. However, because it is the parent’s utility that is being 

maximized and productivity depends on parent’s and children’s time-of-day preferences, it is not 

 

15 As it turns out, it does not make much difference whether we use the nonemployed or nonwork days of the 

employed as our reference group. This is consistent with our supposition that it is the morningness preference of 

children that drives productivity, rather than the eveningness of their parents. Also, research on the nonemployed 

(Frazis and Stewart 2005) has shown that the nonwork days of workers are very similar to the average day of the 

nonemployed. In other results (not presented here), we found the timing of enriching childcare activities of the 

nonemployed to be similar to that of the employed on nonwork days. 
- 12 -

crucial that enriching childcare occur in the mornings—only that there is a difference between 

workdays and nonwork days. 

Figure 2 shows the fraction of parents that are engaged in any type of childcare by time 

of day for full-time employed mothers, part-time employed mothers, full-time employed fathers, 

and nonemployed parents. The graphs for employed parents show the fraction engaged in 

childcare on work and nonwork days. 

Panel (a) shows the graph for mothers who are employed full time. As we would expect, 

workdays and nonwork days are quite different. On workdays, childcare activities are 

concentrated in the mornings and evenings, with few mothers engaging in childcare in the 

middle of the day. On nonwork days, childcare is more evenly distributed throughout the day 

and the peaks are far less pronounced. The fraction providing care is higher on nonwork days 

between 8am until about 5:00pm. Before 8am, there is sharp spike in the percentage of mothers 

who are providing childcare on workdays. After 5:00pm, there is little difference between the 

percentage of mothers providing childcare on workdays and nonwork days 

Compared with mothers who work full time, a higher fraction of part-time employed 

mothers provide childcare between 8:00am and 5:00pm on both workdays and nonwork days 

(panels a and b). Part-time employed mothers who worked on their diary days are more likely to 

be providing childcare in the middle of the day compared with full-time employed mothers who 

worked. On nonwork days full- and part-time employed mothers look more similar to each 

other, although a larger fraction of part-time employed mothers are engaging in childcare at most 

times of the day. 

The graph for full-time employed fathers is similar to the graph for full-time employed 

mothers except that the fraction of fathers providing care at any given time is lower (Panel c). 
- 13 -

Also, the morning spike is smaller for fathers, which may reflect the fact that they are less likely 

than full-time employed mothers to have a spouse who works full time. The fraction of fathers 

providing care on workdays is largest in the morning and the evening, with very few providing 

care in the middle of the day. On nonwork days, the fraction providing care hovers around 10 

percent from 8am to 6pm. From about 6pm on, the fraction of fathers providing childcare is 

about the same on workdays and nonwork days. 

Panel (d) shows nonemployed mothers and fathers. As with employed parents on 

nonwork days, childcare is fairly evenly distributed between 7am and 9pm, although a greater 

fraction of nonemployed mothers provide childcare than do fathers. The fraction of mothers 

providing childcare hovered between 15 and 25 percent between 7am and 9pm, whereas the 

fraction of fathers mostly ranged between 5 and 15 percent. 

Figure 3 shows the same set of graphs for routine care. On workdays for both fathers and 

mothers, this care is concentrated in the morning before work and in the evening after work 

(panels a, b, and c). On nonwork days routine care is more evenly distributed throughout the 

day, although there are still noticeable peaks in the morning and the evening. The graph for the 

nonemployed mothers also shows morning and evening peaks, while the peaks are not noticeable 

for nonemployed fathers (panel d). The morning peak appears to last longer on nonwork days 

than it does on workdays, suggesting that these routine activities may be done later or at a more 

leisurely pace, which could be viewed as a form of shifting. The evening spike associated with 

putting children to bed is performed at about the same time of day by all groups (except 

nonemployed fathers) on both work and nonwork days. 

The same set of graphs for enriching childcare activities is shown in Figure 4. The 

fraction of parents engaged in enriching activities is relatively small at every time of day, which 
- 14 -

reflects the fact that most childcare is routine. Panel (a) shows the graph for mothers who are 

employed full time. Only a small fraction of mothers who worked--about 1 percent--are engaged 

in enriching activities from 8am through mid-afternoon. The fraction is much higher on 

nonwork days, between 3 and 7 percent, with the small spikes occuring in the mid-morning and 

late afternoon. The evening peak is about the same on workdays and nonwork days. Fathers 

who work full time look very similar to mothers who work full time on both workdays and 

nonwork days (panel c). 

The graph for part-time employed mothers (panel b) indicates that they are more likely to 

be engaged in enriching activities earlier in the day on both workdays and nonwork days 

compared to full-time employed mothers and fathers. On nonwork days, the largest fraction is 

engaged in enriching activities in the mid-morning and mid-to-late afternoon, with the afternoon 

fraction being quite a bit higher. The pattern is similar on workdays, although the fraction is 

lower except during the evening. Nonemployed mothers and fathers are very similar to each 

other (panel d). 

These figures make it clear that a small fraction of parents are engaging in enriching 

childcare at any given time, that there are large differences between workdays and nonwork days 

of employed parents, and that nonwork days of employed parents are similar to average days of 

nonemployed parents. 

For our next analysis, it is more convenient to graph the difference between workdays 

and nonwork days in the fraction of parents engaged in enriching activities at each time of day. 

We estimated separate OLS regressions for each time of day between 6:00am and 11:00pm at 5-

minute intervals (204 equations total).16 The dependent variable equals one if the parent was 

 

16 We also estimated logit equations. Logits have the obvious advantage that the results can be expressed as odds 

ratios. However, it is more difficult to see the pattern by time of day because the value of the odds ratio depends on 
- 15 -

engaged in enriching activities at that time and the independent variable of interest is a dummy 

variable that equals one if the individual worked (away from home) during the day. To eliminate 

the effect of shifting enriching childcare activities from workdays to nonwork days and focus on 

timing, we dropped parents who did no enriching care on their diary day.17 We know from Table 

1 that employed parents spend considerably more time in enriching activities on nonwork days 

than on workdays. So to correctly estimate the effect of working on the timing of enriching 

childcare, it is necessary to control for the time spent in these activities on the diary day. We 

also controlled for demographic characteristics and household composition to account for any 

differences between the workday and nonwork day samples, but, as expected, these controls 

make very little difference. 

The three graphs in Figure 5 show the coefficient on the “workday” dummy along with 

upper and lower bounds of the 95% confidence interval. To account for the ATUS’s complex 

sample design, we used replicate weights to compute standard errors.18 

A smaller fraction of full-time employed parents (panels a and c) are engaged in 

enriching childcare activities during normal working hours on workdays compared to nonwork 

days, and a larger fraction is engaged during the after-work evening hours. Keeping in mind the 

small fraction of parents that are engaged in enriching care at any given time, these effects (about 

−0.05 for mothers and −0.10 for fathers) are large and statistically significant at about the 95 

percent level. Thus it appears that these parents shift the time they spent in enriching childcare 

 the probability on nonwork days as well as the difference between work and nonwork days. The probabilities on 

nonwork days are low enough at some times of day that even the small variation that we observe in our data causes 

the odds ratios to vary widely. These results are available from the authors on request. 

17 Our qualitative results are not sensitive to this sample restriction. 

18 As a check, we computed using two alternative procedures: (1) we computed Huber-White standard errors 

clustering on a pseudo-PSU variable that was created by combining ATUS’s pseudo-cluster variable (GEPSEUCL) 

and state, and (2) we computed standard errors using the survey methods commands in STATA with the same 

pseudo-PSU variable. Both of these procedures produced standard errors that were nearly identical to those from 

the replicate-weight procedure. 
- 16 -

activities to less-productive times of day in order to accommodate full-time employment. The 

smaller effects for full-time employed mothers, compared to fathers, could be due to the fact that 

they work fewer hours (34 hours per week vs. 41.5 hours for full-time men). It could also be the 

case that mothers make greater efforts to spend time with their children during higherproductivity times of day.19 Finally, a larger fraction of full-time employed fathers have 

nonworking spouses who can spend time with the children during the day. Thus full-time 

employed fathers are more likely to have a substitute (from the children’s perspective) for their 

time with children during the day. It is worth noting that all of the shifted enriching care is 

playing with children. Reading to children is done almost exclusively in the evening, 

presumably as part of the bedtime routine. 

The coefficients for part-time employed mothers do not show the clear pattern of shifting 

that is present among full-time employed mothers. The coefficients on the worked variable 

fluctuate considerably by time of day, and the coefficients are generally not statistically 

significant at the 95 percent level. The evening peak is lower and of shorter duration, and 

between about 10:00am and 1:00pm the effect of working on the diary day is mostly positive 

(though not statistically significant). To be sure, there are times when the effect is negative, 

large, and statistically significant, but these times are of relatively short duration. Thus, it 

appears that part-time employed mothers spend relatively more time in enriching care activities 

at high-productivity times on workdays. 

Although our results say nothing about causality, it seems likely that one of the reasons 

that mothers work part-time is so that they have the flexibility to schedule work in order to spend 

more time with their children during higher-productivity times of day. This explanation is 

 

19 In results not presented here, we found that when parents worked less than 7 hours on the diary day they tended to 

leave work early rather than going to work later. This effect is moderate, though not statistically significant. 
- 17 -

consistent with the results of Ichino and Sanz de Galdeano (2005), who find that the availability 

of part-time jobs and flexible employment arrangements is a more important determinant of 

maternal employment rates than the availability of formal childcare facilities. Their research 

suggests that many of these part-time employed mothers would choose not to work, rather than 

work full time, if part-time jobs were not available. 

Figure 6 shows how enriching childcare is distributed throughout the day. Among 

mothers and fathers who were employed full time, over 60 percent of the time spent in enriching 

activities on workdays is spent between 5pm and 9pm compared to less than 35 percent on 

nonwork days (panels b, e, and f). On nonwork days about half of the time in enriching activities 

is spent between 8am and 5pm versus 15 to 20 percent on workdays. In contrast, the 

distributions of time spent in enriching activities on workdays and nonwork days are more 

similar to each other for mothers who work part time. On workdays nearly 40 percent of 

enriching childcare activities are done between 8am and 5pm, compared with a little over half on 

nonwork days. A little under 40 percent of enriching childcare is done between 5pm and 9pm on 

workdays, compared to about 25 percent on nonwork days. As a point of comparison, 

nonemployed mothers and fathers spend about half of their time in enriching activities between 

8am and 5pm and only one-quarter between 5pm and 9pm. Thus, the distribution of part-time 

employed mothers’ time in enriching childcare on workdays looks much like that of 

nonemployed mothers. 

Summary and Conclusions 

The time that parents spend in enriching childcare activities is an important parental input 

to child development. The extensive literature on this subject has focused on the amount of time 

spent in these types of activities, but has largely ignored when these activities take place. The 
- 18 -

psychological literature on circadian rhythms suggests that timing matters because people have 

preferences over the time of day that vary systematically with age, with young children tending 

to prefer the morning and adults tending to prefer the afternoon and evening. Other research 

shows that people perform better on complex tasks at their preferred times. This suggests that, 

because enriching care activities are likely to be more complex for young children than for their 

parents, the value of enriching care to the children is greater in the morning than in the afternoon 

or evening, although productivity depends on the parent’s time-of-day preference as well as the 

children’s. 

Our theoretical model predicts that, all else equal, parents will want to spend more time 

in enriching care when that time is most productive. But if these more-productive times of day 

coincide with times when the productivity of market work is high, the model predicts that parents 

will shift enriching care activities to times of day when those activities are less productive. 

Our empirical analysis compares the timing of enriching childcare done by employed 

parents on workdays and nonwork days. The relatively large amount of time parents spend in 

enriching care in the morning and early afternoon on nonwork days is consistent our theoretical 

model and with findings in the psychological literature that children prefer mornings to evenings. 

After controlling for the amount of time spent in enriching activities, we found that full-time 

employed parents shifted time spent in enriching activities to later in the day on workdays. This 

may not seem too surprising because most people work during normal working hours. The effect 

is larger for full-time employed fathers than for full-time employed mothers, which suggests that 

mothers are more willing or better able to adjust their schedules to spend time with their children 

earlier in the day. Although we controlled for the presence of older children in the household, it 

is still possible that they play an additional role in the timing of enriching care. 
- 19 -

The results for part-time employed mothers are intriguing. It appears that part-time 

employed mothers shift enriching childcare activities to a much lesser extent. Thus, our results 

suggest that mothers who work part time do so not only to spend more time with their children, 

but also to spend better time. This result is important because it implies that the greater ability to 

choose when they work is one of the attributes that makes part-time work desirable to working 

mothers. 

Our results also imply that looking only at the amount of time spent in enriching 

childcare activities understates the full impact of parental employment. Combined with the 

results from research on circadian rhythms, they imply that parental time in enriching childcare 

activities on workdays is less valuable for young children because these activities occur at lesspreferred times of day, when these children are less receptive to learning. The time may also be 

less enjoyable for parents because young children tend to be cranky and less cooperative later in 

the day, when they are tired. Parents’ shifting of enriching childcare time from workdays to 

nonwork days mitigates this negative effect somewhat, because it allows parents to spend 

relatively more time with their children at high-productivity times of day. But this between-day 

shifting can only go so far, because young children require daily interaction. 

It is worth noting that these results do not necessarily imply that the children of employed 

parents are worse off. Presumably, these children are in some sort of daycare or preschool, 

where they can participate in enriching activities with their preschool teachers and with other 

children. Whether children are worse off depends on how substitutable this time is for parental 

time. 

The results do suggest one way that parents of young children benefit from flexible work 

schedules and why part-time employed mothers might be willing to accept lower wages. Our 
- 20 -

results also imply that parents would value having childcare facilities at or near their workplace 

so that they could interact with their children during the day on workdays. 
- 21 -

References 

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Childcare Measures in the ATUS and Earlier Time-Diary Studies.” Monthly Labor 

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Bianchi, Suzanne (2000) “Maternal Employment and Time with Children: Dramatic Change or 

Surprising Continuity.” Demography 37, November 2000, pp. 139-154. 

Bianchi, Suzanne (2006) “‘What Gives’ When Mothers Are Employed? Parental Time 

Allocation in Dual Earner and Single Earner Two-Parent Families.” Unpublished 

manuscript, University of Maryland. 

Bianchi, Suzanne, John Robinson, and Melissa Milke (2006) Changing Rythms of American 

Family Life, Russell Sage Foundation, New York. 

Connolly, Marie (2008) “Here Comes the Rain Again: Weather and the Intertemporal 

Substitution of Leisure.” Journal of Labor Economics 26(1), January 2008, pp. 73-100. 

Craig, Lyn (2006) “Where Do They Find the Time? Analysis of How Parents Shift and Squeeze 

Their Time around Work and Child Care.” The Levy Economics Institute Working Paper 

439. 

Frazis, Harley and Jay Stewart (2007) “Where Does the Time Go? Concepts and Measurement in 

the American Time Use Survey.” In Hard to Measure Goods and Services: Essays in 

Memory of Zvi Griliches, Ernst Berndt and Charles Hulten, eds., NBER Studies in 

Income and Wealth, University of Chicago Press, 2007. ) 

Frazis, Harley and Jay Stewart (2005) “What Do Male Nonworkers Do?” Unpublished 

manuscript, Bureau of Labor Statistics. 

Hamermesh, Daniel S., Harley Frazis, and Jay Stewart (2005) “Data Watch: The American Time 

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Hamermesh, Daniel S., Caitlin Knowles, and Mark L. Pocock (2006) “Cues for Coordination: 

Light, Longitude, and Letterman.” Unpublished manuscript, University of Texas - 

Austin. 

Hasher, Lynn, David Goldstein, and Cynthia P. May (2005) “It’s About Time: Circadian 

Rhythms, Memory, and Aging.” In Human Learning and Memory: Advances in Theory 

and Application, ed. by C. Izawa and N. Ohta. Kansas: Lawrence Erlbaum Associates. 

Ichino, Andrea and Anna Sanz de Galdeano (2005) “Reconciling Motherhood and Work: 

Evidence from Time-Use Data in Three Countries.” In The Economics of Time Use, ed. 

by D. Hamermesh and G.A. Pfann. Elsevier B.V., pp. 263-288. 

Kim, Sunghan, Gwenden L. Dueker, Lynn Hasher, and David Goldstein (2002) “Children’s time 

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Paley, Irina (2006) “Right Place, Right Time: Parents’ Employment Schedules and the 

Allocation of Time to Children.” Unpublished manuscript, March 2005, Brown 

University. 
- 22 -

Stafford, Frank and W. Jean Yeung (2005) “The Distribution of Children’s Developmental 

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Elsevier B.V., pp. 289-313. 

Wickersham, Leandra (2006) “Time-of-Day Preference for Preschool-Aged Children,” 

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Social Sciences, School of Languages, Cultures, and World Affairs, College of 

Charleston, Volume 5. 

Winston, Gordon C. (1982) The Timing of Economic Activities. New York: Cambridge 

University Press. 
Figure 1(a) 

 Period 1 Period 2 

 a1* 

γ1f ́(a1) 

 T 

θ1g ́( x1) + λA - λx γ2f ́(a2) 

 a2* 

θ

γ

γ1f ́ θ1g ́ + λA - λx θ2g ́ + λA - λx

Note: Time spent in activity A is measured from the left axis, while time spent in activity X is measures from the 
Figure 1(b) 

 Period 1 Period 2 

 a1* 

γ1f ́(a1) 

 T 

θ1g ́( x1) + λ0A - λx γ2f ́(a2) 

 a2* 

θ

 a10 a20

γ

γ01f ́ 

γ1f ́ θ1g ́ + λA - λx

θ01g ́ + λ0A - λx θ2g ́ + λ0A - λx

θ2g ́ + λA - λx
Total

Workdays 

(away from 

home)

Nonwork 

Days* Total

Workdays 

(away from 

home)

Nonwork 

Days* Total

Workdays 

(away from 

home)

Childcare (with child < 5) 2.0 1.7 2.5 2.7 2.0 3.2 3.1 1.2 0.9 

Routine childcare 1.1 0.9 1.5 1.4 1.0 1.7 1.7 0.5 0.4 Enriching childcare 0.6 0.4 0.8 0.9 0.6 1.1 1.0 0.5 0.4 

Playing with children 0.4 0.3 0.6 0.7 0.4 0.9 0.8 0.4 0.3 Reading to children 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.0 0.0 

Other childcare 0.3 0.4 0.3 0.4 0.4 0.4 0.4 0.1 0.1 Observations 2,043 937 1,106 1,172 421 751 2,163 3,451 1,850 

* Includes days on which the respondent worked at home and did not work away from home. Note: sample restricted to parents age 18 and over with at least one child under age 5 living in the household. All childcare estimates parents were with at least one of their children under age 5. Table 1. Hours spent in childcare by mothers and fathers on an given day, 2003-2006 ATUS annual averages

Mothers F

Employed full time Employed part time

Not 

employed

Employed fu
Figure 2. Childcare (with child less than 5) 

Percent providing childcare by time of day, 2003-2006 annual averages 

a) Mothers, employed full time

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m. 8 p.m. 9 p.m. 10 p.m. 11 p.m.

Percent providing childcare

Worked

Did not work

b) Mothers, employed part tim

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m

Percent providing childcare Worked Did not work

c) Fathers, employed full time

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m. 8 p.m. 9 p.m. 10 p.m. 11 p.m.

Percent providing childcare Did not work

Worked

d) Parents, not employed

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p

m

Percent providing childcare MothersFathers
Figure 3. Routine childcare (with child less than 5) 

Percent providing routine childcare by time of day, 2003-2006 annual average

a) Mothers, employed full time

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m. 8 p.m. 9 p.m. 10 p.m. 11 p.m.

Percent providing routine childcare Worked Did not work

b) Mothers, employed part ti

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m

Percent providing routine care

Did not work

c) Fathers, employed full time

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p.m. 6 p.m. 7 p.m. 8 p.m. 9 p.m. 10 p.m. 11 p.m.

Percent providing routine childcare Worked Did not work

d) Parents, not employed

05

1015202530

6 a.m. 7 a.m. 8 a.m. 9 a.m. 10 a.m. 11 a.m. 12 p.m. 1 p.m. 2 p.m. 3 p.m. 4 p.m. 5 p

m

Percent providing routine childcare Mothers

Fathers
Figure 4. Enriching childcare (with child less than 5) 

Percent providing enriching childcare by time of day, 2003-2006 annual averag

a) Mothers, employed full time

05

1015202530

6 a.m.

7 a.m. 

8 a.m.

9 a.m. 

10 a.m.

11 a.m.

12 p.m.

1 p.m.

2 p.m.

3 p.m.

4 p.m.

5 p.m.

6 p.m.

7 p.m.

8 p.m.

9 p.m.

10 p.m.

11 p.m.

Percent providing enriching childcare Worked Did not work

b) Mothers, employed part t

05

1015202530

6 a.m.

7 a.m.

8 a.m.

9 a.m.

10 a.m.

11 a.m.

12 p.m.

1 p.m.

2 p.m.

3 p.m.

4 p.m.

5 p.m

Percent providing enriching care 

Did not work

c) Fathers, employed full time

05

1015202530

6 a.m.

7 a.m.

8 a.m.

9 a.m.

10 a.m.

11 a.m.

12 p.m.

1 p.m.

2 p.m.

3 p.m.

4 p.m.

5 p.m.

6 p.m.

7 p.m.

8 p.m.

9 p.m.

10 p.m.

11 p.m.

Percent providing enriching childcare Worked Did not work

d) Parents, not employed

05

1015202530

6 a.m.

7 a.m. 

8 a.m.

9 a.m. 

10 a.m.

11 a.m.

12 p.m.

1 p.m.

2 p.m.

3 p.m.

4 p.m.

5 p.m

Percent providing enriching childcare Mothers Father
Figure 5: The Effect of Working on the Fraction of Parents Engaged in 

Enriching Childcare Activities at Different Times of Day 

(a) Full-Time Employed Mothers

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

7am8am

9am

10am11am

Noon

1pm

2pm

3pm

4pm5pm6pm7pm8pm9pm

10pm

(b) Part-Time Employed Mothers

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

7am8am9am

10am11am

Noon

1pm2pm3pm4pm5pm6pm7pm

8pm

9pm

10pm

(c) Full-Time Employed Fathers

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

0.25

7am8am9am

10am11am

Noon

1pm2pm3pm4pm5pm6pm7pm8pm9pm

10pm

Coefficient on Workday Indicator 95% CI 95% CI
Figure 6: Distribution of Time Spent in Enriching by Time of Day 

a) Mothers, full time who worked

0 5 10 15 20 25

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childcare time

b) Mothers, full time who did not w

0 5 10 15 

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childca

c) Mothers, part time who worked

0 5 10 15 20 25

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childcare time

d) Mothers, part time who did not w

0 5 10 15 

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childca
Figure 6: Distribution of Time Spent in Enriching by Time of Day (continued) 

e) Fathers, full time who worked

0 5 10 15 20 25

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childcare time

f) Fathers, full time who did not wo

0 5 10 15 

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childca

g) Mothers, not employed

0 5 10 15 20 25

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childcare time

h) Fathers, not employed

0 5 10 15 

10-11pm

8-9pm6-7pm4-5pm2-3pm

Noon-1pm

10-11am

8-9am6-7am

Percent of total enriching childca
Routine childcare

030101 Physical care of household children

030109 Looking after children as a primary activity

030301 Providing medical care to household children

Enriching childcare

030102 Reading to/with household children

030103 Playing with household children, not sports

030104 Arts and crafts with household children

030105 Playing sports with household children

030106 Talking with/listening to household children

030107 Helping/teaching household children (not related to education)

030201 Homework (household children)

030203 Homeschooling of household children

Other childcare

030108 Organization and planning for household children

030110 Attending household children’s events

030111 Waiting for/with household children

030112 Picking up/dropping off household children

030199 Caring for and helping household children, not elsewhere classified

030202 Meetings and school conferences (household children)

030204 Waiting associated with household children’s education

030299 Activities related to household children’s education, not elsewhere classified

030302 Obtaining medical care for household children

030303 Waiting associated with household children’s health

030399 Activities related to household children’s health, not elsewhere classified

170301 Travel related to caring for and helping household children

180301 Travel related to caring for and helping household children

180302 Travel related to household children’s education

180303 Travel related to household children’s health

Appendix A. Classification of activities among routine care, quality care, and unclassified care