Compute MCTQ average weekly sleep duration

sd_week() computes the average weekly sleep duration for the standard and micro versions of the Munich ChronoType Questionnaire (MCTQ).

See sd_overall() to compute the overall sleep duration of a particular shift for the shift version of the MCTQ.

Usage

sd_week(sd_w, sd_f, wd)

Arguments

sd_w: A Duration object corresponding to the sleep duration on workdays from a standard or micro version of the MCTQ questionnaire. You can use sdu() to compute it.
sd_f: A Duration object corresponding to the sleep duration on work-free days from a standard or micro version of the MCTQ questionnaire. You can use sdu() to compute it.
wd: An integerish numeric object or an integer object corresponding to the number of workdays per week from a standard or micro version of the MCTQ questionnaire.

Value

A Duration object corresponding to the vectorized weighted mean of sd_w and sd_f with wd and fd(wd) as weights.

Details

Standard MCTQ functions were created following the guidelines in Roenneberg, Wirz-Justice, & Merrow (2003), Roenneberg, Allebrandt, Merrow, & Vetter (2012), and from The Worldwide Experimental Platform (theWeP, n.d.).

$\mu$MCTQ functions were created following the guidelines in Ghotbi et al. (2020), in addition to the guidelines used for the standard MCTQ.

MCTQ$^{Shift}$ functions were created following the guidelines in Juda, Vetter, & Roenneberg (2013), in addition to the guidelines used for the standard MCTQ.

See the References section to learn more.

Class requirements

The mctq package works with a set of object classes specially created to hold time values. These classes can be found in the lubridate and hms packages. Please refer to those package documentations to learn more about them.

Rounding and fractional time

Some operations may produce an output with fractional time (e.g., "19538.3828571429s (~5.43 hours)", 01:15:44.505). If you want, you can round it with mctq:::round_time().

Our recommendation is to avoid rounding, but, if you do, make sure that you only round your values after all computations are done. That way you avoid round-off errors.

Guidelines

Roenneberg, Allebrandt, Merrow, & Vetter (2012), Ghotbi et al. (2020), and The Worldwide Experimental Platform (n.d.) guidelines for sd_week() ($SD_{week}$) computation are as follows.

Notes

The average weekly sleep duration is the weighted average of the sleep durations on work and work-free days in a week.
If you are visualizing this documentation in plain text, you may have some trouble understanding the equations. You can see this documentation on the package website.

Computation

$$SD_{week} = \frac{(SD_{W} \times WD) + (SD_{F} \times FD)}{7}$$

Where:

$SD_{week}$ = Average weekly sleep duration.
$SD_{W}$ = Sleep duration on workdays.
$SD_{F}$ = Sleep duration on work-free days.
$WD$ = Number of workdays per week ("I have a regular work schedule and work ___ days per week").
$FD$ = Number of work-free days per week.

* $W$ = Workdays; $F$ = Work-free days.

References

Ghotbi, N., Pilz, L. K., Winnebeck, E. C., Vetter, C., Zerbini, G., Lenssen, D., Frighetto, G., Salamanca, M., Costa, R., Montagnese, S., & Roenneberg, T. (2020). The $\mu$MCTQ: an ultra-short version of the Munich ChronoType Questionnaire. Journal of Biological Rhythms, 35(1), 98-110. doi:10.1177/0748730419886986

Juda, M., Vetter, C., & Roenneberg, T. (2013). The Munich ChronoType Questionnaire for shift-workers (MCTQ$^{Shift}$). Journal of Biological Rhythms, 28(2), 130-140. doi:10.1177/0748730412475041

Roenneberg T., Allebrandt K. V., Merrow M., & Vetter C. (2012). Social jetlag and obesity. Current Biology, 22(10), 939-43. doi:10.1016/j.cub.2012.03.038

Roenneberg, T., Wirz-Justice, A., & Merrow, M. (2003). Life between clocks: daily temporal patterns of human chronotypes. Journal of Biological Rhythms, 18(1), 80-90. doi:10.1177/0748730402239679

The Worldwide Experimental Platform (n.d.). MCTQ. https://www.thewep.org/documentations/mctq/

Examples

## Scalar example

sd_w <- lubridate::dhours(4)
sd_f <- lubridate::dhours(8)
wd <- 5
sd_week(sd_w, sd_f, wd)
#> [1] "18514.2857142857s (~5.14 hours)"
#> [1] "18514.2857142857s (~5.14 hours)" # Expected

sd_w <- lubridate::dhours(7)
sd_f <- lubridate::dhours(7)
wd <- 4
sd_week(sd_w, sd_f, wd)
#> [1] "25200s (~7 hours)"
#> [1] "25200s (~7 hours)" # Expected

sd_w <- lubridate::as.duration(NA)
sd_f <- lubridate::dhours(10)
wd <- 6
sd_week(sd_w, sd_f, wd)
#> [1] NA
#> [1] NA # Expected

## Vector example

sd_w <- c(lubridate::dhours(4.5), lubridate::dhours(5.45))
sd_f <- c(lubridate::dhours(8), lubridate::dhours(7.3))
wd <- c(3, 7)
sd_week(sd_w, sd_f, wd)
#> [1] "23400s (~6.5 hours)"  "19620s (~5.45 hours)"
#> [1] "23400s (~6.5 hours)"  "19620s (~5.45 hours)" # Expected

## Checking second output from vector example

if (requireNamespace("stats", quietly = TRUE)) {
    i <- 2
    x <- c(sd_w[i], sd_f[i])
    w <- c(wd[i], fd(wd[i]))
    lubridate::as.duration(stats::weighted.mean(x, w))
}
#> [1] "19620s (~5.45 hours)"
#> [1] "19620s (~5.45 hours)" # Expected

## Converting the output to 'hms'

sd_w <- lubridate::dhours(5.45)
sd_f <- lubridate::dhours(9.5)
wd <- 5
x <- sd_week(sd_w, sd_f, wd)
x
#> [1] "23785.7142857143s (~6.61 hours)"
#> [1] "23785.7142857143s (~6.61 hours)" # Expected
hms::as_hms(as.numeric(x))
#> 06:36:25.714286
#> 06:36:25.714286 # Expected

## Rounding the output at the seconds level

sd_w <- lubridate::dhours(4.5)
sd_f <- lubridate::dhours(7.8)
wd <- 3
sd_week(sd_w, sd_f, wd)
#> [1] "22988.5714285714s (~6.39 hours)"
#> [1] "22988.5714285714s (~6.39 hours)" # Expected

mctq:::round_time(sd_week(sd_w, sd_f, wd))
#> [1] "22989s (~6.39 hours)"
#> [1] "22989s (~6.39 hours)" # Expected