Farmer test plots have become a staple for production agriculture. These plots can range from simple side-by-side demonstration plots to a replicated research study. The rush of harvest often creates a challenge for harvesting these plots. Yield monitor data were collected from field scale plots in multiple states to assess ability to measure on-farm research. Grain mass was also measured for each plot with a weigh wagon or certified scale. The variability of yield monitor error (standard deviation) was not correlated with the magnitude of the error (mean). Thus calibration in and of itself will likely not result in more consistent yield monitor error. Determining if treatments or observations from non-replicated studies are different will be challenging. Depending on the chosen probability level, this data indicate that distinguishing a 3 to 9 percent difference was possible. Statistical analysis of replicated trials results in similar conclusions with reference and yield monitor data. Mass flow rate is one factor impacting yield monitor error.