Retrospective Study

{
  "id": "MLC-T-ENV-024222",
  "term": "Retrospective Study",
  "field": "Environment",
  "definition": "1. An epidemiological study which compares diseased persons with non-diseased persons and works back in time to determine exposures.\n\n2. A kind of nonexperimental study in which all the phenomenon investigated occurs prior to the onset of the study. Further, the samples of retrospective studies are usually chosen by the value the responses take. T his latter point creates special conceptual issues regarding causality, and the composition of comparison samples (see matches) is especially important. Advantages of retrospective samples is that they allow one to investigate phenomena that are either unlikely or undesirable to occur in the future; further, since all key events occur in the past, retrospective studies can often be undertaken economically.\n\n3. A study in which investigators select groups of patients that have already been treated and analyze data from the events experienced by these patients. These studies are subject to bias because investigators can select patient groups with known outcomes.\n\n4. A kind of nonexperimental study in which all the phenomenon investigated occurs prior to the onset of the study. Further, the samples of retrospective studies are usually chosen by the value the responses take. T his latter point creates special conceptual issues regarding causality, and the composition of comparison samples (see matches) is especially important. Advantages of retrospective samples is that they allow one to investigate phenomena that are either unlikely or undesirable to occur in the future; further, since all key events occur in the past, retrospective studies can often be undertaken economically. [NIST/SEMATECH 2005b]",
  "subject": "Policy and guidance",
  "references": [
    "Drinking Water Technical & Legal Terms",
    "NIST/SEMATECH 2005b",
    "NLM/NICHSR 2004",
    "Thesaurus of Terms Used in Microbial Risk Assessment"
  ],
  "url": "https://mlchart.com/terminology/environment/retrospective-study/"
}