Table 1 Study characteristics of preclinical immune checkpoint blockade experiments. Numbers in parentheses represent percentages of total number of studies

Total number of mice

13,811

Internal validity

Randomization

60 (37)

Sample size justification

13 (8)

Blinded assessment of treatment effect

9 (6)

Experimental flow

8 (5)

Dose response

22 (14)

Construct validity

Baseline characterization

5 (3)

Disease match

80 (50)

Age match

11 (7)

Mechanistic response to treatment

144 (90)

External validity

Model replication

86 (54)

Research purpose

Translational claim

133 (83)