Dr. Charley Martinez teaches agricultural and resource economics at the University of Tennessee. Martinez is interested in the factors that influence a bull-buying decision, with the goal of removing bias. When asked about decisions, a producer may feel compelled to say they put more emphasis on EPD evaluation than they actually do, or oversell the importance they place on economic indexes. Visual appraisal often takes place in-person, but how a bull is presented in a catalog also matters.
Martinez and his team started researching in 2021. Early experiments evaluated whether producers were using EPD to make selections, and tested their ability to predict value. Next, Martinez purchased state-of-the-art eye-tracking equipment, which reveals where a person’s eye goes first, how long their attention is focused, and other behaviors. Martinez’s first study posed the question, “Do EPDs matter?” After finding that the answer was yes, the next question was, “What EPDs matter?”
EPD systems have developed dramatically since their introduction. The earliest EPDs were for basics: birth weight, weaning weight, yearling weight and milk, for example. In the early 2000s, percentile rankings became part of the system. During this same time, researchers started developing economic selection indexes to simplify and improve selection decisions.
Economic selection indexes are typically placed at the far right-hand side of the overall EPD profile. Martinez says this may have an unintended effect on behavior. “Visual cognition literature supports the idea of ‘What comes first is seen first,’ which is known as the primacy effect.” Recent eye-tracking studies suggest that people often skip information on the far-right, especially when the information is dense or busy.
The objectives of Martinez’s latest study were: To understand the influence of different EPD profile layouts on buyers’ accuracy of seedstock bull price prediction; to understand producers’ characteristics that affect accurate decision-making when buying a bull; to understand producers’ accurate decision-making across different states and breeds; and to understand the factors that affect producers’ accurate prediction of quality-differentiated bulls.
The team collected data through “lab in the field” experiments, using the eye-tracking technology. Across several states, 208 participants looked at 18 bulls, with the challenge of predicting value. These bulls had been sold, which gave a baseline for their real-world value.
Participants looked at a looping video of each bull, as well as an EPD profile. The bulls were Angus, Simmental and Hereford, chosen to represent high, average and low EPD profiles. The control group saw what is typically presented in a bull sale catalog. The treatment groups either saw the EPD in typical order with percentile ranks, the EPD in typical order without percentile ranks, the EPD in reverse order with percentile ranks, or the EPD in reverse order without percentile ranks.
The participants were given minimum and maximum values to keep their estimation within. They were also surveyed on their involvement in the beef industry, the breeds used in their operation, age, income, comfort with risk and other general measures. The survey also asked if participants used EPDs in real life, or genomically enhanced (GE) EPDs.
This study showed that participants were most successful at predicting value when the EPDs were presented in reverse order, and when percentile ranks were displayed, with the index measures on the left. Participants who utilize GE-EPD were better at predicting the price of the bulls. People who reported being more risk-seeking were more likely to be wrong on the bull predictions. Those who reported being more comfortable with delayed gratification were more likely to accurately predict the value of the bulls.
The eye-tracking technology data showed the percentage of time that people spent “fixated” on an area or simply “gazing.” People overwhelmingly spent more time looking at an animal’s phenotype, versus EPD and indexes. Only 11% gazed at the indexes, with 10% fixating. The opposite was true for phenotype, with over 97% gazing, and 100% fixating. Martinez shared that this data shows that more education is needed on indexes, as well as how to differentiate the measures across breeds.
The results of this study also bring up the important question of how producers should lay out their bull sale catalogs. With the number of EPD and data points available, choosing what matters most is a challenge, and it’s easy to create information overload.
EPD ranks and percentiles, as well as placing economic indexes on the left, improved buyers’ ability to accurately predict bull value. “Our study suggests that emphasizing economic selection indexes in catalogs can enhance producers’ evaluation accuracy by better helping them connect merit with economic value,” Martinez shared. — Lilly Platts, American Simmental Association managing editor
