Breedplan – Outliers and what to do about them?

As a part of the on-going verification of the performance information being analysed by BREEDPLAN, a number of data checks are carried out. One of these checks is the identification of outlier records.


What is an Outlier?
Every time a BREEDPLAN analysis is run, the variation between the performance information of animals within each contemporary group is examined. If correctly formed each contemporary group will only include animals of similar type that have had equal opportunity to perform under similar conditions. While a certain degree of variation is performance is expected within each contemporary group, when the difference between a performance record for an animal and the average of all animals in the contemporary group is much greater than we would normally expect for the trait measured, the record for this animal is identified as an outlier. (As seen in attached graph)


Why do Outliers occur?
Outliers may occur for a variety of reasons. These include:

  • Incorrect measurements may have been recorded (e.g. transcription errors, data collection errors, data entry errors).
  • Incorrect animal details may have been recorded (e.g. date of birth, sex).
  • Correct management grouping may not have been used (e.g. sick animal not placed in separate group).
  • Animals may be significantly genetically superior/inferior to their contemporaries.

Once an outlier record has been identified, an outlier report is sent to the owner of the animal asking them to check the performance record in question. This report gives the owner of the animal the opportunity to review the performance data and correct or verify the outlier record.


What should I check upon receipt of an Outlier Report?
In the outlier report, the outlier animals are marked in bold with the symbol in both the left hand and right hand margins and adjacent to the Raw Observation. Also reported are the other animals with which the outlier animals have been directly compared within the BREEDPLAN analysis. Different contemporary groups are separated in the outlier report by blank lines. When investigating an outlier record, the owner of the animal should check that:

  1. The performance information has been correctly recorded.
  2. The animal details have been correctly recorded.
  3. The animal is being analysed in the correct contemporary group.


How do I correct and/or verify Outlier Records with BREEDPLAN?

Once the outlier record has been checked, it is important that the owner of the animal contacts staff at their BREEDPLAN processing centre to either correct or verify the outlier record.
Importantly, if the owner of the animal does not correct or verify an outlier record, then the outlier record will be excluded from all future BREEDPLAN analyses.

OUTLIER REPORTS can be found in your DOWNLOADS section of your Breedplan Login.

For more information regarding outliers, or for assistance in the interpretation of an Outlier Report, please contact Pedigree Cattle Services.