*2.1. Data*

During the first lockdown in the UK (between May and June 2020), we collected a dataset aimed to capture the paid and unpaid working practices of dual-earning heterosexual co-habiting parents in paid employment with children under 18. We focus on this population because the nature of flexible working and the question of division of domestic work is significantly different for this group compared to others—such as those with stay-at-home partners. We first gathered our data using an online survey panel (Prolific academic) to gain access to 560 respondents, which was the maximum number of respondents in this panel who met our selection criteria. To supplement this, we collected additional 324 cases through social media channels such as Twitter, Facebook, and targeted

partner organisations that distributed the survey through their internal links/mailing lists. Due to the nature of the research question and sample sizes, we were unable to examine same sex couples or couples where one or more partners does not identify as either male or female. Limiting the sample to heterosexual co-habiting parents of children under 18, where both partners were in employment before the pandemic with no missing data for key variables resulted in a total of 692 cases. Since the data includes detailed information about the respondents and their partners, alongside information about the household—such as the division of housework, childcare and income between the couple, we are able to look at how 692 couples divided domestic work during the first lockdown period.

Given the lack of knowledge we have about dual-earner co-resident parent population in the UK, we cannot guarantee the representativeness of this data set. Examining some of the key demographics of the data (see Appendix A, Table A1), our respondents are slightly higher educated than the general population (55% of men and 66% of women in our sample have tertiary education compared to 45% of men and 49% of women of the general population aged between 25–64). Accordingly, our sample has a higher average household income (median/mode household income is between £50,000 to £60,000) compared to median household income in the UK (of £30,000). However, these discrepancies could also be explained by the fact that we only examine dual-earning couples who generally have higher household incomes. Further indicators such as the number of hours worked by male (13% worked part time before the pandemic) and female partners (50% worked part-time before the pandemic), as well as the number of children (1.7 on average) and others are representative of UK households. We have more female respondents (76%) than male respondents. The main reason for this is because we did not restrict the respondent's gender when we were recruiting participants. This was largely due to the fact that we wanted to maximise the number of cases that met our criteria (dual earning employed cohabiting couples with children), and only few did. What is more, in our convenient sample of respondents drawn from social media, and selection of partner organisations, more women responded to our request. We use gender as a control variable to take into account the different perceptions men and women have of how housework and childcare is divided [74].

## *2.2. Dependent Variables*

The dependent variable used for this paper is the division of housework and childcare between couples, and the additional involvement of fathers in housework and childcare during the lockdown compared to before. In the survey, we asked participants how they are/have been dividing housework and childcare tasks with their partners before and since the lockdown (see also for studies using similar approaches, [75,76]). Based on the literature, we distinguished between six categories of housework/childcare, namely, two routine housework including "cooking", "house cleaning/laundry", one non-routine housework, namely, "DIY (home, garden, car) maintenance, transport". We also include routine childcare noted in the survey as "generally looking after child(ren)", and two nonroutine childcare activities, including "playing or entertaining child(ren)", and particularly of interest during the pandemic, "educating your child(ren)/supporting with homework (including home learning)". Respondents could answer "I do (did) it all", "I do (did) more of it", "we share(d) it equally", "my partner does (did) more of it", and "my partner does(did) it all". From this, we derived a variable indicating the division of housework– where the values indicate (1) male partner does all of it, (2) male partner does more of it, (3) shared equally, (4) female partner does more of it, and (5) female partner does all of it, derived for each of the six areas. The "total amount" variable refers to the mean of the six categories considered. We also asked respondents "SINCE the Coronavirus lockdown, has your time on the following tasks changed?". The same was asked about their partners' time, distinguished between the six different areas. Due to the skewness of the distribution, we recoded this 5-scale response category dichotomously: 1 indicates that the respondent (or their spouse) is spending more time on the task than before the lockdown, 0 indicates

that the respondent (or their spouse) is spending less time or the same amount of time. As a robustness check, we also examined it as a continuous variable (see Appendix B, Table A2).
