Summary

This article covers the contents of the strata tab.

Table of Contents

Requirements

The Strata tab must have at least one Factor and one Stratum defined. The ‘Uses Randomization’ property in the Configuration tab must be set to “yes” for all studies with Strata defined.

In the study, subjects are identified by different factors such as sex, age and BMI. Each study will have its own set of unique factors that are used to randomize the subjects.

  1. Configuration ID: Enter the number that corresponds to the Configuration ID in the Configuration worksheet that you want to use.
Note: Strata applied at the study level will be used for all sites.


  1. Factor ID: Enter a unique number for the ID. These are usually assigned sequentially starting with the number, 1.
  2. Factor Name: Enter a name for the Factor.
  3. Factor Weight: Enter a positive decimal value for the weight that the factor should carry for the study.
Note: Only the Minimization algorithm uses the Factor Weight but Factor Weights are not required for Minimization to work.


The Factor Weight should be defined within the study’s protocol.

  1. Repeat the steps for each Factor


Define Factor Levels

Factor Levels are used to divide each factor into different subgroups. Like Factors, Factor Levels are used for randomization purposes only.

Example: The Factor, sex, could be divided into two Factor Levels: male and female.

Note: If the trial is configured to use the Minimization Algorithm, the Factor Levels section must be completed in order for Minimization to work.


  1. Factor ID: Enter the Factor ID that corresponds to the factor for which you are defining subgroups.
  2. Factor Level ID: Enter a unique number for the Factor Level ID. These are usually assigned sequentially starting with the number, 1.
  3. Factor Level Expression: Enter the expression that uniquely defines the properties of the Factor Level.
    • Example: The Expression for the Factor Level, female, could be: ‘#screening.demog.sex == 2′
  4. Repeat the steps for each Factor Level


Define Individual Stratum

Each Stratum represents a unique combination of the Factor Level Expressions. Study subjects are assigned to one of the study’s Strata based on their factor qualifications.

  1. Stratum ID: Enter a unique number for the ID. These are usually assigned sequentially starting with the number, 1.
  2. Stratum Name: Enter a short name for the Stratum.
  3. Stratum Expression: Enter the expression that uniquely defines the properties of the Stratum.
    • Example: If the Factors were sex and age range and the factor levels were male, female, above the age of 20 and below the age of twenty, one Stratum could be Young female with the Stratum Expression, #screening.demog.sex == 2 AND #screening.demog.age_icd < 20
  4. Factor Levels: Enter the Factor Level IDs that correspond to the Factors used for each Stratum separated by a comma.
  5. Repeat the steps for each Stratum



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