The researchers developed a new method to measure how efficiently pigs use their food over time. By using a special statistical model, they were able to calculate this measure, called residual feed intake (RFI), in a way that is not influenced by other pig traits. They tested this method on data from over 2000 pigs and found that it provided stable and accurate estimates of RFI and its genetic relationships with other traits. This new approach is better suited for studying how efficiently pigs convert food into growth, even when some data points are missing.