Table 1. List of measures against risks of bias included in this study.

Measure	Definition	Bias
Allocation Concealment	Concealment of allocation sequence from those assigning subjects to treatment groups, until the moment of assignment.	Selection Bias
Randomization	Allocation of study subjects randomly to treatment groups across the comparison, to ensure that group assignment cannot be predicted.	Selection Bias
Blinding	Keeping the persons involved in an experiment (i.e. experimenter, data collector, outcome assessors) unaware of the treatment allocation.	Attrition Bias, Detection Bias, Performance Bias
Sample Size Calculation	Appropriate a priori determination of number of study subjects for a given test setup that allows for a detection of a treatment effect given the power to find an effect of a defined size.	“Avoiding wastage of animals”
Inclusion and Exclusion Criteria	A priori defined characteristics which describe on which basis subjects will be included in the study or how they need to be treated in case of attrition.	Attrition Bias, Selective Reporting
Primary Outcome	A priori defined main variable of interest, on which the treatment effect is measured; with sample size calculation being based on it.	Selective Reporting
Statistical Analysis Plan	A priori definition of statistical methods by which the primary outcome variable is analyzed at the end of the study.	Attrition Bias, Selective Reporting

Definitions adapted from van der Worp et al. [5], CONSORT (www.consort-statement.org), the Cochrane Collaboration (methods.cochrane.org).