Reflections from the Field: Ground-Truthing Healthy Food Outlets

As part of their six-week public health placement, Master of Nutrition and Dietetic students Noa Blair and Jack Ko have been supporting our project on Healthy Food Environments Around Transport Hubs. One of their key tasks involved ground-truthing: verifying digital data by visiting locations in person. Here, they share their reflections and lessons learned from the process.

"Ground-truthing is the gold standard of information verification. It involves actually going to locations to determine whether data that has been collected digitally is accurate and complete.  However, this process can be incredibly labour intensive and time consuming, so here are some things we did to make it more efficient.

In our study, we used ground-truthing to verify data collected from Google Maps on what healthy food outlets are accessible in eight areas in Sydney, Australia. 

Noa and Jack on the ground!

Preparation is key to streamline the process. We took each of the healthy food outlets and plotted them on a digital map so that we could easily visualise the route. This way, we were able to see how spread out the food outlets were and effectively determine how to best divide them into two groups for us to individually check.

We created a hard copy checklist to list out all the outlets to be assessed and arranged them in alphabetical order. We then planned our route and public transport to be the most efficient for our time constraints. 

Flexibility is also crucial to maintaining the efficiency of ground-truthing. It is important to utilise time-saving alternative methods that fit the ground-truthing purpose.

In our case, we performed regular ground-truthing on most of the locations and made phone calls to less accessible outlets and outliers to ensure that it is time-efficient yet still creates reliable data. 

By combining careful preparation with flexible strategies, ground-truthing can remain a highly effective and efficient method for verifying the accuracy of digital data."