Background Adherence to ethical guidelines and regulations and protecting and respecting the dignity and autonomy of participants by obtaining a valid informed consent form (ICF) prior to participation in research are crucial; The subjects did not add signatures next to the corrections made to signatures or dates on the ICF, Multiple signatures in other fields, ICF missing/missing signature, Incorrect ICF version Signed after modification, Correction tape used to correct signature, Impersonated signature, Non-research-member signature, however, ICFs are often not properly completed, (...) which must be addressed. This study analyzed ICF signing errors and implemented measures to reduce or prevent these errors. Methods We used the plan–do–check–act (PDCA) cycle to help improve the correctness and validity of ICF signing. Results Interim and final reports from January 2016 to February 2020 including 363 ICFs were studied. The total proportion of correct ICF signatures (200, 83.3%) following the PDCA intervention was significantly higher than that before the intervention (P < 0.05). Analysis of the types of signing error demonstrated that signature errors were significantly reduced after the intervention, particularly for subjects did not add signatures next to the corrections made to signatures or dates on the ICF (16, 6.7%) and impersonated signature (0; P < 0.05). Conclusions The proportions of other error types—multiple signatures in other fields, missing or unsigned ICF, incorrect signature order, incorrect ICF version, use of correction tape to correct signature, and non-medical profession members signing the ICF—did not differ significantly. (shrink)