Dummy factor

{
  "id": "MLC-T-CHM-003474",
  "term": "Dummy factor",
  "field": "Chemistry",
  "definition": "A factor entered in an experimental design as a placeholder because it is known not to influence the measured response, for example an imaginary switch between two settings that are in fact identical. Whatever effect it seems to show can only reflect random variation, so its estimated effect gives an estimate of the repeatability standard deviation. In Plackett-Burman designs, where the run count must be a multiple of four, dummy factors occupy any columns left unused.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "experimental design",
    "response"
  ],
  "references": [
    "PAC, 2016, 88, 407. 'Vocabulary of concepts and terms in chemometrics (IUPAC Recommendations 2016)' on page 414 (https://doi.org/10.1515/pac-2015-0605)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/dummy-factor/"
}