However, a missing value is stored as a very large number in the Stata data file.
Most commands ignore missing values by default.
Some commands, such as tabulate , have an option to display missing if you want to see how many missing observations there are. Other commands, however, may use missing values in a way that will surprise you. For example, the replace command does not ignore missing values. Here is a simple example to demonstrate how replace and recode handle missing values differently. The first replace command changes every value that's greater than 1 to 1.