When reading data, what does the option MISSOVER do?

The option MISSOVER is utilized in SAS when reading data and refers specifically to how the input pointer behaves when it encounters missing values in the data set. When MISSOVER is specified, it instructs SAS to not advance to a new line if it reaches the end of a record before all expected variables have been read. Instead, if there are fewer fields on the line than expected, SAS will assign missing values to the variables that did not receive data.

This behavior is particularly useful when working with data that may have variable-length records, as it allows for the processing of lines in a controlled manner without skipping to the next line prematurely. As a result, you can effectively manage observations that may not adhere to having values for every variable in a consistent manner.

Other options focus on different aspects that are not appropriate in this context. Skipping entire observations would not be the function of MISSOVER; instead, the intent is to continue processing the current line. Similarly, filling missing values with zeros and reporting the number of missing values are actions that would require additional instructions beyond what MISSOVER does. The primary purpose of MISSOVER is to modify the behavior of the input pointer, ensuring that it remains on the same line unless explicitly directed otherwise.