The best database design in the world can be utterly destroyed by poor quality data. Although no data collection is perfect, there is a certain quality threshold which, if fallen below, can make a database impossible to use.
Most researchers can cope with 'dirty data' but it is up to the creators to minimise the errors.
This will make their own research more productive and avoid the need to engage in a massive retrospective correction phase. Typing itself can leave an exceptionally large window for human error, and even the most fastidious typists will make mistakes. The transcription process is nothing new to historians, yet it is reasonable to argue that transcribing into a database is a subtly different task which in general requires more accuracy and the use of validation methods. One method for overcoming many of the vexed burdens of historical sources is to apply wide-ranging data standardisation and coding schemes. The application of standards and codes can introduce a high level of accuracy in data, and is more amenable to database system requirements.