A New Way to Time Change of Address Could Sharpen Health Research
When people move homes, it changes their exposure to pollution, green space, healthcare services, and stress—factors that affect health. However, health records don't always reflect these moves right away. In a new study, published in the International Journal of Population Data Science (IJPDS), researchers from University College London looked at how quickly address changes are recorded in health data, and how to estimate when those changes happen to help researchers track people’s environments more accurately.
The team focused on the health records of around 40,000 people, looking at when their addresses changed at the neighbourhood level (not the exact address). They found that over 95% of the participants had address changes that could be tracked in health data, which allowed us to compare the timing of these changes.
Knowing where and when people live is crucial for studying health issues like asthma. If health records only update addresses when a person visits their doctor, there can be a delay in capturing where they live, which can affect research results.
Three simple ways to estimate the timing of a move were tested:
- N-1 Rule: Assume the person moved on the exact day the change was recorded.
- Median Rule: Set the change date in the middle of the two recorded addresses.
- Random-Beta Rule: Estimate the move happening shortly after the recorded change, based on how records are usually updated.
All three methods gave very similar results, with about 78-79% agreement between the health data and the cohort data on where people lived and when. Each rule makes a different assumption, but they all point to a similar picture of where someone lives.
It’s important to make these assumptions clear, especially when studying groups who move more often, like families or people in unstable housing.
There are some limitations, however. People whose health records were up to date are more likely to be included in this study, which might make the results look better than they are for everyone. Also, by looking at neighbourhoods rather than exact addresses, small moves within the same area wouldn’t show up.
Overall, while timing isn’t perfect, choosing a clear rule to estimate when people move can reduce confusion and help researchers study how places affect health more accurately. The key takeaway: use a clear rule, explain the assumptions behind it, and check it against other reliable data when possible.
What different groups can do to improve data capture for research:
- Health Service Users: Update your address with your GP to help improve both your care and health research.
- Data Teams: Regularly ask participants about their addresses, keep track of move-in dates, and clearly define how address changes are recorded.
- The Public: We need an open discussion about how location data is collected, why it matters, and how to do it safely and transparently.
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Dr Joseph Lam, Research Fellow, Population, Policy & Practice Department, University College London