Keyed entries were transmitted directly into the computer.

Following data transcription for a particular section of the population schedule
the computer performed a series of on-line edits and consistency checks of the data.

When a check indicated that a transcribed value was suspect,
the computer instructed the clerk to rekey the item.

A computer program compared the second sampling and data transcription with the original
and required that the verifying clerk rekey any discrepancies.

Compiled from National Archives and Records Administration. “Data Transcription Procedures.” Chapter 2. Sample Selection and Data Processing PRocedures. Public Use Samples of Basic Records from the 1940 Decennial Census of Population and Housing. 1% Stratified Sample File NN3-29-89. 2.1-2.3. 20 June 1994. PDF file.