PMC:7543267 / 53784-53903 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T399","span":{"begin":0,"end":119},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"High attrition could lead to selection bias with those who are more motivated or engaged overrepresented in the sample."}