Editing Cronbach's alpha (section)

===Methods to increase reliability===
Despite the costs associated with increasing reliability discussed above, a high level of reliability may be required. The following methods can be considered to increase reliability.

Before [[data collection]]:
* Eliminate the ambiguity of the measurement item.
* Do not measure what the respondents do not know.<ref>{{Cite journal|last1=Beatty|first1=P.|last2=Herrmann|first2=D.|last3=Puskar|first3=C.|last4=Kerwin|first4=J.|date=July 1998|title="Don't know" responses in surveys: is what I know what you want to know and do I want you to know it?|url=https://pubmed.ncbi.nlm.nih.gov/9829099/|journal=Memory (Hove, England)|volume=6|issue=4|pages=407–426|doi=10.1080/741942605|issn=0965-8211|pmid=9829099|access-date=2023-02-20|archive-date=2023-02-20|archive-url=https://web.archive.org/web/20230220140847/https://pubmed.ncbi.nlm.nih.gov/9829099/|url-status=live}}</ref>
* Increase the number of items. However, care should be taken not to excessively inhibit the efficiency of the measurement.
* Use a scale that is known to be highly reliable.<ref>Lee, H. (2017). Research Methodology (2nd ed.), Hakhyunsa.</ref>
* Conduct a pretest - discover in advance the problem of reliability.
* Exclude or modify items that are different in content or form from other items (e.g., reverse-scored items).

After data collection:
* Remove the problematic items using "alpha if item deleted". However, this deletion should be accompanied by a theoretical rationale.
* Use a more accurate reliability coefficient than <math>\rho_{T}</math>. For example, <math>\rho_{C}</math> is 0.02 larger than <math>\rho_{T}</math> on average.<ref name="PK">{{cite journal|last1=Peterson|first1=R. A.|last2=Kim|first2=Y.|title=On the relationship between coefficient alpha and composite reliability|journal=Journal of Applied Psychology|volume=98|issue=1|pages=194–8|date=2013|doi=10.1037/a0030767|pmid=23127213}}</ref>