Using the Animal Calculator

Responsible Office: Office of Animal Research Support (OARS)
Effective Date: Wednesday, June 15, 2016

Overview

The calculation of animal numbers is one of the most important design components of the experiment-based structure of MAPS.  This quick guide provides an overview of how MAPS uses two methods of providing animal numbers for a given experiment. You can utilize one or both methods to accurately reflect your sample size.  

Animal Calculator – Variables that Impact the Number of Groups 

This section uses the concept of variables to help you calculate the number of animals required for an experiment.

When building your experimental paradigm, describe how the experiment will be conducted and the various branches or variations that will be presented to your animal population. These variations will be added within this section as variables.

Remember that variables are always multipliers.  Considerations for approximating numbers should include, but are not limited to, repetitions, animal availability, strains, dependent variables, numbers/group, statistical significance, experimental time points/endpoints. 

Example: Repetitions: in order to identify and estimate variability, each experiment will be repeated 3 times; Drugs: in order to evaluate the effects of immunoglobulins, 4 different antibodies will be tested (see below); Study Endpoints: in order to evaluate the effects of other variables over time, mice will be euthanized at day 1, 7, 30 and 90; Animals/Group: based on a power analysis, each group will have five mice; Number of strains/genotypes: in order to evaluate the effects of genotype, 4 different mouse strains will be used (see below). 

Animal calculator

In this example, the experiment has 5 key variables that affect the experimental paradigm.  

  1. To add a variable, click Add.
  2. Enter all relevant information.

Manual Animal Numbers

  1. Variable Type
  2. Variable Count
  3. Description of variable (Note: The “Description” serves as the justification for the number of animal requested, therefore should include a reason why the number listed needs to be that number)
  4. Click OK to finish or if you wish to add more variables click Add Another.

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