Which input method requires data values to be separated by spaces?

The input method that requires data values to be separated by spaces is list input. This method reads data from an external file or from an inline data step, treating any sequence of non-space characters as a separate value. In list input, the default delimiter is whitespace (spaces or tabs), making it efficient for datasets where values are naturally separated by these characters.

When using list input, you can read data into a dataset without specifying the variable's position, unlike column or formatted input. Thus, if your data is organized in a way where fields are separated by spaces, list input is the most suitable approach. This flexibility allows for higher adaptability for a variety of unformatted datasets, particularly when the exact positions of values are not consistent.

Other input methods serve different purposes: formatted input allows for the reading of data with specific formats defined for the values, column input is designed for fixed-width data where the position of each item is known, and direct input typically refers to a method where data is manually entered into a SAS program. Each of these methods has its own context and use cases, but for situations where values are space-separated, list input is the appropriate technique.