Missing values in time use variables

Are the missing values on time use variables counted as 0 minutes for the aggregate bls variables?

for example bls_work_search has more 0 than positive values, is it because they did not include those activities or because they did not respond to the amount of time spent on them?

Many thanks,

Since the ATUS interview is designed in a such a way that respondents are asked their activities through a 24-hour period, there is no concept of a missing value for time spent on an activity. In other words, given your example, observations with bls_work_search==0 indicate that the respondent did not spend any time in the 24-hour period he/she was surveyed about on the activities specified by that aggregation of variables.