Table 2 Risk of bias, Score interpretation: Zero (0) if the variable is not reported in the article, one (1) if the variable is reported but inadequate, Two (2) if the variable is reported and adequate (\) not applicable

Clearly stated aim

The aim of the study is essential to make an unbiased assessment of the findings of studies with excavated human skeletons.

2

2

2

2

2

2

Primary outcome

The primary outcome is essential to make an unbiased assessment of the findings of studies with excavated human skeletons.

2

2

2

2

2

2

Ancestry/ethnicity distribution

Reporting the ancestry/ethnicity of the sample is essential to determine possible outcome bias in studies with excavated human skeletons.

2

2

2

2

2

2

Condition of the sample

Reporting the condition of the sample is essential to make an unbiased assessment of the findings in studies with excavated human skeletons.

1

2

2

2

1

2

Sample preservation

Reporting the preservation methods used on the sample is essential to make an unbiased assessment of the findings in studies with excavated human skeletons.

1

2

2

2

1

2

Age-at-death distribution

Reporting of the age-at-death distribution of the sample and the method for its estimation is important to make an unbiased estimation of the outcome of studies with excavated human skeletons.

2

2

2

2

0

2

Sex distribution

Reporting of the sex distribution of the sample and the method for its estimation is important to make an unbiased estimation of the outcome of studies with excavated human skeletons.

2

2

0

1

2

2

Time period

Reporting of the time period of the sample and the dating method used is important to make an unbiased estimation of the outcome of studies with excavated human skeletons.

2

2

2

1

1

2

Method of measurement

Reporting the method(s) of measurement is important to make an unbiased estimation of the outcome of studies with excavated human skeletons.

2

2

2

2

2

2

Statistical test

Reporting appropriate statistical tests in accordance with the study type and primary outcome of the study is essential to make an unbiased estimation of outcome of studies with excavated human skeletons.

2

2

2

1

2

2

Selective or incomplete reporting

Selective or incomplete outcome reporting may bias the findings of studies with excavated human skeletons.

2

2

2

2

2

2

Blind Testing

Blind Testing of research staff may reduce bias in certain settings of studies with excavated human skeletons.

2

2

\

\

\

\

Baseline equivalence

In comparative studies with excavated human skeletons, reporting the baseline equivalence of the groups to be compared is essential to make an unbiased estimation of the outcome.

2

2

\

\

\

\