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Input Data File

The input data file contains a dependent variable and an independent variable or covariate. The dependent variable values can either be directly provided in the input data file or Joinpoint can calculate the values if their components are provided. For example, Joinpoint can calculate age-adjusted rates if the associated count, population, standard population, and adjustment variable (typically age group) are provided.

The dependent variable may be an age-adjusted rate, crude rate, count, percentage, proportion, or other numeric value. The independent variable is typically the year. The data file may also contain standard errors (for rates) and by-variables such as age group, sex, or race. These variables (or columns of data) do not have to be in any particular order, but the data file (or rows of data) must be sorted by the by-variables and the independent variable. You identify the dependent variable by specifying whether it is calculated or provided, the type of variable to be modeled (i.e., crude rate, percent), and then selecting the appropriate items on the right (i.e. count, population, rate).

SEER*Stat provides an easy mechanism for creating Joinpoint data files and setting the controls on the Joinpoint Input File tab. In SEER*Stat, select "Matrix | Export" when viewing the SEER*Stat matrix to create a file in the format of a Joinpoint Input Data File. In Joinpoint, select "New”>”Session…" from the File menu and then select the SEER*Stat Dictionary file. The input data file name, variable names and locations, and file format information will be loaded from the SEER*Stat Dictionary.

The Heteroscedastic Errors Option is automatically set from the SEER*Stat Dictionary, depending on whether or not the standard errors are included. If they are not included, Constant Variance (Homoscedasticity) is selected. If they are included, Standard Error is selected.