Answer： Roots of good documentation principles are in the ICH-GCP where source data and source document is first defined. Key attributes for good documentation were first described by US-FDA in the form of ALCOA (attributable, legible, contemporaneous, original and accurate). These are also adapted by World Health Organization (WHO). These criteria evolved with time. EMA has added some more ‘letters’ to describe qualities of good source documentation particularly for electronic documentation. Attributable: It should be clear who has documented the data. Legible: Readable and signatures identifiable. Contemporaneous: The information should be documented in the correct time frame along with the flow of events. If a clinical observation cannot be entered when made, chronology should be recorded. Acceptable amount of delay should be defined and justified. Original: Original, if not original should be exact copy; the first record made by the appropriate person. The investigator should have the original source document. Accurate: Accurate, consistent and real representation of facts. Enduring: Long-lasting and durable. Available and accessible: Easily available for review of treating physicians and during audits/inspections. The documents should be retrievable in reasonable time. Complete: Complete till that point in time. Consistent: Demonstrate the required attributes consistently. Credible: Based on real and reliable facts. Corroborated: The data should be backed up by evidence.