Table 3.

Examples of common errors and suggested remedies

Category	Type	Example	PMID	Suggested remedy
Irreproducibility		“Thus, our own present findings, along with those from other laboratories, contradict major findings from our previous report.”	20134478	Increase redundancy in experimental design, more replications, aim for more robust statistics
Lab error	Data entry	“Incorrect data were found to have been included on the case report forms and subsequently in the databases of some studies.”	15504385	Double entry or the creation of duplicate databases (81)
		Data pertaining to a dopamine receptor D4 (DRD4) polymorphism, rs4646984, was mistakenly pasted into a column containing serotonin transporter gene (5-HTTLPR) data.	20050156
	Contamination	“The cell line ACC3 which was used in the study … was reportedly found cross contaminated with HeLa.”	22359742	Cell line authentication and good cell line practice (24, 25)
	Selection	“The mice that had been ordered for the experiments described in our published article were, in fact, mistakenly mice that were doubly deficient in … receptor.”	21209288	Double check critical reagents, preferably by a second individual
	DNA related	“A mistake was made during the sequencing of the smk-1 allele from the…strain that was used in our studies.”	20584918	Validation of results by independent methods and incorporating more redundancy into experimental design
		Methodological problem that resulted in a misidentification of a pseudogene as a novel mutation.	21135394
		“Resequencing of the cDNA clone obtained in the Y2H screen resolved a particularly GC-rich region upstream of the calcyon start codon that had been misread before and indicated that the calcyon coding sequence is out of frame with the GAL4 activation domain.”	17170272
Data analysis	Statistical analysis	These errors relate to the numbers of families included and several erroneous values in the tables. This failure led, among others, to an extremely high correlation between the male subjects' mates and subjects' parents in the facial proportion jaw width/face width.	19129144	Statistical consultation and independent assessment of database integrity
		“Errors in the statistical calculations and interpretation of the analyses presented in that article.”	16983065
	Computation	“Due to a decimal place error for body weight…we have had to reanalyze our data upon reanalysis with the corrected value we have found our conclusions to change in a way that does not warrant publication.”	17193703	Double check critical calculations, preferably by a second individual
		“Dilution errors were made in calculating	7594697
		the numbers of bacilli present in the lungs.”
		“We rechecked the original data and found that the equation used to correct for differences in weights between groups of animals was incorrect.”
			3882286
Programming	Coding error	As a result of a bug in the Perl script used to compare estimated trees with true trees, the clade confidence measures were sometimes associated with the incorrect clades.	17658946	Validate program outputs with known databases and results
Controls		“A change in international convention of testing occurred between the time that the majority of controls were investigated and the time that the majority of patients were investigated. We incorrectly assumed these tests to be entirely equivalent.”	9303950	Identification of correct control group

Example quotations are taken from the retraction notice. PMID refers to the retraction notice.