Multi-wave studies

IBM® SPSS® Data Collection Survey Reporter can be used to analyze data from tracking or multi-wave studies. The purpose of a tracking study is to repeatedly measure the same variables and determine their changes over time. For example attitudes, awareness, or buying habits can be measured every month in a consistent fashion. In IBM® SPSS® Quantum™/IBM® SPSS® Quanvert™ such projects are referred to as multi-wave projects.

While the questions for each ‘wave’ of a tracking study are consistent, they are not exactly the same. From wave to wave, questions and categories can be added or removed. For example, if a new brand comes onto the market, the brand would be added to the brand list. Similarly, the analyst may decide, that based on the analysis for the waves to date, additional questions are required for greater customer insight.

Survey Reporter allows you move from one wave of the study to the next without having to recreate the variable edits and table definitions:

• Variable edits are retained. Variable edits are changes to the variable that do not result in the variable axis expression changing (for example, when the variable label is updated). Variable edits are retained without impacting changes to the variable’s element list.

• Variable axis expressions are retained. Axis expressions on a variable are used to change how the elements for the variable are tabulated. For example, an axis expression can be used to hide, combine, or net elements. The axis expression can also be used to add new elements, such as user-defined and statistic elements. You can control whether changes to the element list, from one wave to the next wave, will be automatically reflected in the axis expression. Elements added in a wave will also be added to any variable axis expressions. In some cases, such as variables edited to only show certain brands, automatically adding new elements may not be desired.

• Table edits are retained. Similar to axis expressions on variables, axis expressions can be added to a variable as part of a table definition. Table axis expressions are not updated to reflect the variable definitions in the latest wave. For example, if an element has been added to a variable and that variable has been edited on the table, the new element will not be included in the table. However, if the variable has not been edited on the table, the new element is included.