1. A method for specifying a subset of data, comprising: receiving a first input at a user interface of a computing device for a first field of a natural language expression, the first input indicates a first data value for the first field; accessing options for a second field of the natural language expression that are determined based on the first data value and data stored in data group; displaying the second field and the options for the second field; receiving a second input at the user interface for the second field of the natural language expression, the second input indicates a second data value for the second field from the options for the second field; accessing options for a third field of the natural language expression that are determined based on the second data value and data stored in the data group; displaying the third field and the options for the third field; receiving a third input at the user interface for the third field of the natural language expression, the third input indicates a third data value for the third field, the second data value indicates a relationship between the first data value and the third data value that exists in the data group, a result of receiving the third input is an updated version of the natural language expression that includes the first data value, the second data value and the third data value as natural language; and accessing and reporting a subset of the data group that corresponds to the natural language expression that includes the first data value, the second data value and the third data value as natural language.