The same number must represent the same category across every variable

All categorical variables should be recoded using 0 and 1

The numerical codes should be treated as continuous measurements

The meaning of each code must be documented separately for each variable

Keep a record of the changes, the reason for each change, and the rule used

Delete the original values without recording the changes

Only document corrections that change the study conclusion

Correct the identified values directly in the dataset to ensure that the analysis can proceed efficiently

Replace 999 with the maximum observed age

Replace 999 with age 0

Exclude the coded missing value from the calculation and document the missing-value code

Include 99 because it is an error when entered the numerical value

Convert the derived variable into a continuous score

Remove one of the original variables to avoid duplication

Define and document the exact rule used to construct the variable

Choose the coding after seeing which category has the highest frequency

Generate the frequency distributions and resolve the discrepancies when interpreting the results

Replace all unusual values with the median before generating the frequency distributions

Review and clean the dataset, verify entries, and apply the predefined coding and missing-value rules

Proceed with the analysis because frequency distributions are descriptive and therefore not affected by these problems

The variable can no longer be analyzed

Inconsistent coding may cause one category to be treated as multiple categories

There are no apparent problems, as all responses are positive

The participants must be excluded

Treat all ages as missing because age should not contain decimals

Automatically change 27.5 to 28

Automatically round every age to the nearest whole number

Check the questionnaire before deciding whether the value is valid

Delete the participant from the dataset

Change both answers to No

Change both answers to Yes

Review the questionnaire and determine whether the discrepancy can be resolved

Median and variance

Minimum and maximum only

Mean and standard deviation

Median and interquartile range

A coding consistency check

A citation check

A spelling check

A range check