Table 1

Demographic, socioeconomic, lockdown and mental health measures

 Measure Description Demographic Age Collected for caregivers and children, reported in years. Families and children were differentially affected by lockdown depending on whether children were attending early education centres (day care) or school. This is because schools and early education centres were closed for different, and varying periods of the pandemic. Caregivers of school aged children were required to facilitate home learning, which was arguably more difficult for caregivers of young (compared with older) children. Similarly, families were required to care for young children when early education centres closed, which made it difficult to work from home and also balance other responsibilities. Child age was used as a proxy for these experiences, and categorised to represent preschool (0–4 years), primary/elementary school (5–11 years) and high school (12–17 years). Gender Collected for caregivers and children: response options ‘male’, ‘female’, ‘other’. Two caregivers and no children identified as ‘other’. Before the 2020 Australian census, ‘other’ gender data were not collected for the Australian population, so it was not possible to calculate weights for these caregivers. Hence, they were dropped from the analysis, and the gender variable was dichotomised into ‘female’ compared with ‘male’. Sole caregiver Question ‘are you the sole (single) parent or carer of a child 17 years of age or younger?’, binary response options ‘yes’ (one caregiver household) compared with ‘no’ (multicaregiver household). Caregiver education Question ‘what is the highest level of schooling/education you have completed?’. Responses were trichotomised into three categories that meaningfully represented education as a socioeconomic measure for Australians: (1) ‘year 12 or less’ (response options: less than year 10, year 10 or equivalent (eg, school certificate), year 12 or equivalent); (2) ‘vocational training certificate’ (response options: trade/apprenticeship (eg, carpenter), certificate/diploma (eg, Cert IV Childcare)); or (3) ‘university degree’ (response options: undergraduate university degree, postgraduate university degree (eg, Masters, Doctorate, PhD). Caregiver country of birth Question ‘were you born in Australia?’, binary response options ‘yes’ (born in Australia) compared with ‘no’ (outside Australia). Home language Question ‘do you speak a language other than English at home?’, binary response options ‘yes’ (other than English) compared with ‘no’ (English). Cultural or linguistic diversity A composite of the two above variables, caregiver country of birth and home language, to represent respondents who answered ‘yes’ to either or both items compared with ‘no’ (answering no to both items). Socioeconomic and lockdown Job/income loss during COVID-19 Three items drawn from the CoRonavIruS Health Impact Survey caregiver version13: ‘what changes in employment or income have occurred in your household due to coronavirus/COVID-19?’ (binary response options ‘yes’ compared with ‘no’) including: ‘job loss by one caregiver’; ‘job loss by two caregivers’ and ‘reduced total household income’. A binary variable describing any job loss (by one or two caregivers) or reduction in income due to COVID-19 (compared with not) was created. Low income (<$A1000) A binary variable based on current total household income before tax, categorised into 10 options ranging from ‘less than$A500 per week’ to ‘more than $A3000 per week’, plus ‘prefer not to say’. In 2021, to protect against the economic fallout of lockdown, the Australian federal government rapidly implemented a suite of short-term financial supports, which included an unemployment supplement (‘JobSeeker’) which doubled recipients’ social welfare benefits from$A550 to $A1100 a fortnight, and a wage supplement for eligible businesses to retain their workforce (‘JobKeeper’). These social policy changes represented some of the largest (although temporary) in Australia’s history and were so significant that, by September 2020, levels of poverty and housing stress in Australia were substantially lower than the levels directly preceding COVID-19. To capture any relationships between income poverty and mental health, we created a binary variable summarising low income (‘less than$A1000 per week’ compared with more) based on Australian thresholds.14 n=767 caregivers preferred not to report income, so this variable should be interpreted with caution. Could not afford essential items Eight items adapted from the Household, Income and Labour Dynamics in Australia Survey Wave 18 Household Questionnaire Material Deprivation Module15 asking ‘In the last month, because of money pressure did you miss or put off’ (binary response options: ‘yes’ compared with ‘no’): mortgage or rent repayments; electricity, gas, water bills; food; healthcare; prescription medicines; home or car insurance; mobile phone bills; and internet. A binary summary variable was created to denote ‘any material deprivation’ inability to pay for one or more essential items compared with ‘none’. Current lockdown All Australian states and territories experienced a first national, 10-week lockdown from 23 March to 1 June 2020. Victoria experienced a second extended and more severe, 20-week lockdown from 8 July to 23 November 2020. There were several short (less than a week) lockdowns in the intervening months across states, before New South Wales experienced its second extended period of lockdown, which began incrementally on 26 June 2021. Victoria experienced its fifth (in total) lockdown from 16 to 27 July 2021, before an extended lockdown subsequently began a week later on 5 August 2021. Current lockdown was therefore categorised as follows.The national lockdown had eased for the collection of the June 2020 poll, so no (denoted ‘N’ in tables 2 and 3) Australians were in lockdown. Thus, the number/proportion not in lockdown represents the whole cohort (and is equal to the ‘overall’ numbers/proportions at top of tables 2 and 3).For the September 2020 poll, only residents of metropolitan Melbourne in the state of Victoria were in lockdown (denoted ‘Y’ for ‘yes’) compared with all other Australians (N). This was categorised according to respondents who reported living in Victoria and living in ‘metropolitan’ compared with ‘regional/rural’ areas.By July 2021, many states/territories were going in and out of lockdown, and this question was added into the poll and reported on directly with the question ‘are you currently under stay-at-home orders or restrictions due to COVID-19 (also known as ‘lockdown’)?’, responses ‘yes’ compared with ‘no’. Total length of lockdown Trichotomous variable based on total length of lockdown experienced by each state/territory. By 31 July 2021, the total length of COVID-19 lockdown was greatest for the state of Victoria (‘Vic’, total 31 weeks); followed by the state of New South Wales (‘NSW’, total 15 weeks) and then all ‘other’ states and territories (total range 10–12 weeks). The following geographical categories were used as a proxy for total length of lockdown: (1) Victorian (most), (2) NSW and (3) other (least). Mental health Caregiver mental health 6 items of the Kessler-6 (K6) assessing caregivers’ self-reported anxiety and depressive symptoms encountered in the last 4 weeks. Scored on a 5-point Likert scale from 1 ‘none of the time’ to 5 ‘all of the time’. Summarised into (1) a continuous total score and (2) a binary variable indicating ‘poor mental health’ (total score 19 or more) compared with not (total score 6–18).16 Perceived impact of the pandemic on mental health A 5-point item adapted from UK Young Minds Matter Study,17 describing the perceived impact of COVID-19 on mental health, dichotomised into negative (‘small negative/large negative’) compared with positive (‘none/small positive/large positive’). Reported by caregivers for (1) themselves and (2) each child.