Ranking quarter horse sires via models of offspring performance.

This research paper analyzes data on American Quarter Horse racing performance, with the specific aim of identifying and ranking the most successful sires based on the performance of their offspring.

Research Purpose and Methodology

• The study’s overarching goal was to evaluate American Quarter Horse sires based on their offspring’s racing performance. The ranking devised from this analysis could potentially offer a new perspective on the value of sires and shed light on those that could offer investors a higher return despite correspondingly low stud fees.
• The researchers utilized a 2016 Equibase dataset, which detailed Quarter Horse starts in North America. From the racing data, they calculated a speed z-score as a measure for each horse’s performance. This score was constructed from the race times and distances, taking into account factors such as track, jockey, trainer, and weather conditions that could potentially influence speed.

Mixed Effects Models and Statistical Criteria

• Mixed effects models were key to the study’s methodology. These models were applied to various subsets of the data, including data grouped by race distance and number of sire offspring.
• The researchers considered the sire categorical variable as a random effect. By using different statistical criteria, they optimized the model.
• Moreover, the researchers changed the constructed models by including different random and fixed effects, and then extracted the conditional modes of the sire effects from these models.

Implication and Value of the Study

• The research uncovered that even a sire with a low stud fee could still produce offspring with a high-ranking performance based on the z-score model. This important finding suggested that the offspring of such “bargain” sires might perform remarkably well and offer investors profitable returns despite the relatively low initial investment.
• Consequently, the study’s unique methodology and results challenge the traditional method of sire valuation, which typically prioritizes high rankings for offspring earnings and winners.
• The novel approach to sire ranking, as presented in this research, therefore, contributes significantly to the field, potentially influencing future strategies of horse racing investments and breeding.