I came across this video which really explains this issue in a little over one minute.
Missy Bauer looks at this issue and demonstrates the “square foot” method for determining loss.
2 kernels in a square foot area = 1 bushel per acre yield loss (Watch the video)
From here, more checks should be made in the harvested areas and in the non-harvested areas.
Check the harvested area, to see if the header speed needs to be adjusted.
Look in the rows where the kernels could be blown out for kernels that may have come out as a result of low moisture.
Some good information here and just another way that growers are always checking on ways to improve their harvest.