How many specimens go through the statistical analysis?

IMPReSS sets a minimum number of specimens for each procedure, typically 7 females and 7 males (see the table below). The DCC reviews quality control and criteria to decide whether to export raw data to the CDA.

This number relates to the animals that enter the procedure, some of them may not complete all the experimental assays due to health or experimental issues. Once the CDA receives the data, the statistical pipeline is initiated. The criteria for the statistical analysis vary depending on the data type:

• Continuous Analysis Pipeline: Requires four data points per genotype-sex group, except for the Auditory Brain Stem Response screen, which requires only one data point per genotype-sex group.
  
• Categorical Analysis Pipeline: Requires at least one data point per genotype-sex group.
  

While IMPReSS criteria are met at the procedure level, they may not be met at the parameter level. It is possible that although the procedure is carried out it is not possible to obtain measurements for all the parameters, due to experimental or welfare reasons. Usually for these cases a status code is submitted to justify the lack of data and this can be taken into account before the data goes through the statistical pipeline. In rare cases, such as with Eye Morphology and Combined SHIRPA and Dysmorphology data, the procedure set up requires a value even when no data can be obtained and the number of specimens analysed may be lower for these parameters, because categories with “No data” are excluded from the analysis.

Several phenotypes are assigned, based on information provided by experts, instead of being analysed during the statistical pipeline. In addition, analysis of data contributed by the pain working group and 3i project was assessed by external professionals and is not processed by the statistical analysis pipeline.