Table 1

Extraction results

frequency (%)
Adequate choice of sample size4168
Blinding of outcome assessment4168
Choice of statistical methods for inferential analysis3863
Randomised allocation of animals to treatment3863
Concealed allocation of treatment3152
Recording of the flow of animals through the experiment3152
A priori statements of hypothesis3050
Selection of appropriate control groups2948
Characterisation of animal properties at baseline2847
Addressing confounds associated with setting2338
Definition of outcome measurement criteria2338
Reporting on genetic background2338
Matching or balancing sex of animals across groups2033
Degree of characterisation and validity of outcome1932
Consistency of outcome measurement1830
Monitoring emergence of confounding characteristics in animals1830
Precision of effect size1830
Study of dose–response relationships1830
Addressing confounds associated with experimental setting1728
Establishment of primary and secondary end points1728
Reporting on breeding scheme1627
Assessment of outcome at late/relevant time points1525
Independent replication1525
Matching or balancing treatment allocation of animals1525
Specification of unit of analysis1525
Randomisation for analysis1423
Replication in different species or strains1423
Standardised handling of animals1423
Addressing confounds associated with anaesthesia or analgesia1322
Replication in different models of the same disease1322
Addressing confounds associated with treatment1220
Management of conflicts of interest1118
Treatment response along mechanistic pathway1118
Interstudy standardisation of experimental design1017
Assessment of multiple manifestations of disease phenotype915
Use of multiple time points measuring outcomes915
Definition of treatment813
Interstudy standardisation of end point choice813
Pharmacokinetics to support treatment decisions813
Randomised distribution of animals in the animal facilities813
Use of validated assay for molecular pathways assessment813
Faithful delivery of intended treatment712
Addressing treatment interactions with clinically relevant comorbidities610
Any additional elements that do not fit in the list above610
Comparability of control group characteristics to those of previous studies610
Critical appraisal of literature or systematic review during design phrase610
Define programmatic purpose of research610
Replication at different ages610
Replication using variations in treatment58
Optimisation of complex treatment parameters47
Replication at different levels of disease severity47
Research within multicentre consortia47
Preregistration of study protocol and analysis procedures35