COVID-19
Population Report.

Population mobility during Alert Level 4

Mobility index for 2021 lockdown vs 2020 lockdown

8 September 2021

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How is our population mobility data produced?

Data Ventures is working together with the major telecommunication companies in New Zealand.

Using the aggregated and anonymised mobile data[*] provided to us, along with Stats NZ expertise, Data Ventures has created population estimates of residents and visitors in New Zealand every hour down to suburb level. By looking at how the population in different areas changes over the day, we get an idea of how many people are moving in and out of areas around the country. We use this information to create our population mobility index. Read more in the footnotes page.

Alert Level 4 in 2021 and 2020 – national population mobility

The recent national Alert Level 4 lockdown was shorter than the first Level 4 lockdown in 2020 and came into place with very little warning.

Because of this, it’s worth looking at how the two lockdowns compare in terms of population behaviours – did we get straight back into old habits?

In this section, we compare our population mobility index during the 2020 and 2021 Level 4 lockdowns.

In 2021, we saw a sharp drop in mobility, as there was less than a day between the lockdown announcement and lockdown starting. In 2020, mobility fell more gradually as we moved through alert levels.

Once Alert Level 4 started, population mobility in the recent lockdown was remarkably similar to the first Level 4 lockdown in 2020. On average, New Zealanders were just as good at staying home during this lockdown as they were the first time.

Population mobility during Alert Level 4

Mobility index for 2021 lockdown vs 2020 lockdown

Our mobility measure is based on estimates of how many people are moving in and out of areas around New Zealand. The mobility index represents a percentage difference from normal mobility for the same day of the week. For example, an index value of -50 means people are moving around 50% less than usual.

For this report, we’ve defined normal mobility based on the period from six weeks before each Level 4 started to one week before. This allows us to exclude the period of unusual activity in 2020 from when the borders were closed six days before Alert Level 4 started.

Population behaviours – population mobility across different kinds of areas

By looking at mobility in different types of areas across the country, we get a better understanding of how New Zealanders' habits compare between the two Level 4 lockdowns.

Here, we show our population mobility index during each Level 4 lockdown in six key types of areas in New Zealand. We used the population patterns from before COVID-19 to identify these areas. Refer to our notes[*] at the end of this report to understand a bit more detail about how we classified these areas.

In most area types, mobility was similar between the two lockdowns. Retail, workplace, and tourism areas saw the biggest decreases in mobility both years – unsurprising, given the typical activities in these areas are highly restricted at Level 4. The biggest difference between the two lockdowns was in transit areas, where spikes in mobility were higher during the 2021 lockdown.

Note: Click on the graphs to view a larger version.

retail

2020

2021

recreational

2020

2021

residential

2020

2021

tourism

2020

2021

transit

2020

2021

workplace

2020

2021

Alert Level 4 in 2021 and 2020 – regional population mobility

Here, we show the mobility index during the 2020 and 2021 Alert Level 4 lockdowns for each of the 16 regions of New Zealand. This lets us see how different parts of New Zealand were affected by lockdown.

The drop in mobility during Alert Level 4 varied a lot between regions in both 2021 and 2020. This does not necessarily mean any region was worse at following the lockdown rules – mobility fell more in regions where there is usually more non-essential movement.

For example, in Southland, mobility fell only around 50% in both lockdowns (compared to the national average of 65%). Southland has a large proportion of essential workers, so this smaller drop in mobility was likely because many Southlanders were still going to work or visiting essential services.

Note: Click on the graphs to view a larger version.

northland

2020

2021

Average population mobility across regions

In this section, we’ve plotted the average mobility index for each of the Alert Level 4 lockdowns in the 16 regions of New Zealand.

This comparison gives us a summary of both population mobility in each lockdown, and the difference between the two lockdowns. The wider the horizontal line between the dots for each region, the more different the mobility between the two lockdowns.

From this figure, we can see that in the South Island, mobility was generally lower during the recent lockdown than the first Level 4 lockdown in 2020. In the North Island, mobility was slightly higher this time around.

Population mobility during Alert Level 4

Average mobility index for 2021 lockdown vs 2020 lockdown