Dependent Variable

The dependent, or response, variable is the variable being tested in the model. You can either provide your dependent variable values in the input data set or you can have Joinpoint calculate them from other variables in the input data set (e.g. a crude rate can be calculated from variables with the count and the population).

Run Type

Calculate the Dependent Variable	This option should be selected if you want Joinpoint to calculate your dependent variable. Joinpoint can calculate Crude Rates, Age-Adjusted Rates, Proportions and Percentages. The table below documents which variables are required for each type of dependent variable. Please note that if Joinpoint calculates the dependent variable, it will also compute the associated standard errors.
Use Dependent Variable Provided In Data File	This option should be selected if you are providing Joinpoint with your dependent variable values. For some analysis types, the standard error is also required. Please reference the table below for more information.
Delay Adjusted Data	This option is only available if a SEER*Stat dictionary (DIC) file is used for the session that contains delay adjusted statistics. Joinpoint will read in and analyze the delay statistics for each cohort. See Delay Adjusted Statistics for more information.
Delay & Non-Delay Data	This option is only available if a SEER*Stat dictionary (DIC) file is used for the session that contains delay adjusted statistics. Joinpoint will read in and analyze both the delay and non-delay statistics for each cohort. See Delay Adjusted Statistics for more information.

Types of Dependent Variables Accepted by Joinpoint:

The following dependent variable types can be analyzed by Joinpoint:

Count	A count is typically a number of “events” (i.e. cancer cases or deaths. Joinpoint will accept counts in fractional form (e.g. 410.375).
Crude Rate	A crude rate is the number of cases (or deaths) occurring in a specified population, usually expressed as the number of cases per 100,000 population at risk. Joinpoint will accept counts and populations in fractional form (e.g., 410.375). \(cruderate =\ \frac{count}{pop} \times\ 100,000\)
Age-Adjusted Rate	An age-adjusted rate is a weighted average of crude rates, where the crude rates are calculated for different age groups and the weights are the proportions of persons in the corresponding age groups of a standard population. The age-adjusted rate for an age group comprised of the ages x through y is calculated using the following formula. \(aarate_{x-y} = \sum_{i=x}^{y} \left[ \left( \frac{count_i}{pop_i} \right) \times\ 100,000 \times\ \left( \frac{stdpop_i}{\sum {}_{j=x}^{y} stdpop_j} \right) \right]\) Where count is the number of cases in the ith age group, pop_i is the relevant population for the same age group, and stdpop_i is the standard population for the same age group. If count_i and pop_i are both zero, Joinpoint treats that rate as zero. Joinpoint will not allow the unusual event where popi is zero but count_i is non-zero. If count_i is greater than zero and pop_i is zero, Joinpoint will set pop_i to be equal to count_i in order to compute the interim crude rate. Joinpoint will accept counts, populations and standard populations in fractional form (e.g., 410.375). For a detailed explanation on how to compute age-adjusted rates, see How to Compute Age-Adjusted Rates.
Proportion	A proportion is a ratio of a numerator to a denominator where the result is between 0 and 1. Joinpoint will not analyze cohorts that have proportions greater than 1 when such proportions are calculated. Jointpoint will accept numerators and denominators in fractional form (e.g., 410.375). \(proportion = \frac{numerator}{denominator}\)
Percent	A percent is a fraction or ratio with 100 understood as the denominator. Joinpoint will not allow percentage values greater than 100 when such percentages are calculated. Jointpoint will accept numerators and denominators in fractional form (e.g., 410.375). \(percent = \frac{numerator}{denominator} \times\ 100\)
Other	Select this category for all other types of numeric variables that do not fall into one of the previous categories (i.e. temperatures over time).

Rates Per:

Though Crude Rates are usually expressed as the number of cases per 100,000, when Joinpoint computes Crude Rates, it provides users with several ‘rates per’ options. When age-adjusted rates are computed by Joinpoint, the same ‘rates per’ options are provided for the Crude Rate component. They are:

100
1,000
10,000
100,000
1,000,000

Standard Error Calculations:

When Joinpoint computes the Dependent Variable, the following formulas will be used to compute the associated standard errors.

Standard Error for Crude Rate

This calculation assumes that the counts have Poisson distributions.

\(SE_{crude} = \frac{\sqrt{count}}{population} \times\ 100,000\)

Standard Error for an Age-Adjusted Rate

This calculation assumes that the counts have Poisson distributions. Suppose that the age-adjusted rate is for an age group comprised of ages x through y.

\(SE_{AArate} = \sqrt{\sum_{i=x}^{y} \left( \frac{stdpop_i}{\sum {}_{j=x}^{y} stdpop_j} \right)^2 \times\ \left( \frac{count_i}{population_i^2} \right)} \times\ 100,000\)

Standard Error for Proportions and Percentages

For consistency, assume that percents are transformed to proportions before analysis.

\(SE_{proportion} = \sqrt{\frac{p_i \left( 1 - p_i \right)}{n_i}}\)

Where p_iis the proportion and n_i is the sample size of the ith observation.

\(SE_{percentage} = \sqrt{\frac{p_i \left( 1 - p_i \right)}{n_i}} \times\ 100\)

Edits performed on the Dependent Variable:

When a session is executed, Joinpoint will first edit the input data file. For a list and description of all data errors and warnings produced by Joinpoint, please see the "Job Execution - Errors and Warnings" help section.

Variables:

One or more of the following variables will need to be specified in the input data file depending on the Calculated/Provided, Type, and Heteroscedastic Errors Options selections:

Count Variable
Population Variable
Age-Adjusted Rate
Standard Error - this variable can be found in within the Heteroscedastic/Correlated Errors Option box and is shown only for the applicable Heteroscedastic option.
Adjustment Variable
Standard Population
Numerator Variable – this variable replaces the “Count” variable when appropriate
Denominator Variable – this variable replaces the “Population” variable when appropriate

Joinpoint does allow any variable value to be provided in fractional form (e.g. 410.375).

Calculate	Type	Heteroscedastic Errors	Required Variables	Required Variables	Required Variables	Required Variables
No	Count	Constant Variance	Count
No	Count	Standard Error	Count	Standard Error
No	Count	Poisson Variance	Count
No	Crude Rates	Constant Variance	Rate
No	Crude Rates	Standard Error	Rate	Standard Error
Crude Rates	Poisson Variance	n/a
No	Age-Adjusted Rates	Constant Variance	Rate
No	Age-Adjusted Rates	Standard Error	Rate	Standard Error
No	Age-Adjusted Rates	Poisson Variance	n/a
No	Proportion	Constant Variance	Proportion
No	Proportion	Standard Error	Proportion	Standard Error
No	Proportion	Poisson Variance	n/a
No	Percent	Constant Variance	Percent
No	Percent	Standard Error	Percent	Standard Error
No	Percent	Poisson Variance	n/a
No	Other	Constant Variance	Other
No	Other	Standard Error	Other	Standard Error
No	Other	Poisson Variance	n/a
Yes	Count	Constant Variance	n/a
Yes	Count	Standard Error	n/a
Yes	Count	Poisson Variance	n/a
Yes	Crude Rates	Constant Variance	Count	Population
Yes	Crude Rates	Standard Error	Count	Population
Yes	Crude Rates	Poisson Variance	Count	Population
Yes	Age-Adjusted Rates	Constant Variance	Count	Population	Age Group	Standard Pop
Yes	Age-Adjusted Rates	Standard Error	Count	Population	Age Group	Standard Pop
Yes	Age-Adjusted Rates	Poisson Variance	n/a
Yes	Proportion	Constant Variance	Count	Population
Yes	Proportion	Standard Error	Count	Population
Yes	Proportion	Poisson Variance	n/a
Yes	Percent	Constant Variance	Count	Population
Yes	Percent	Standard Error	Count	Population
Yes	Percent	Poisson Variance	n/a
Yes	Other	Constant Variance	n/a
Yes	Other	Standard Error	n/a
Yes	Other	Poisson Variance	n/a