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Sometimes a form is nearly identical at every data collection point, but there is a slight difference in the question for some items. For example, at baseline the prompt is "what's your highest pain rating in the last two weeks?", whereas at follow-up, the prompt is "What's your highest pain rating since the last visit?" There Note that the data entry prompt is part of the data definition (i.e., tied together with how the variable is defined , e.g., a number with the prompt "Age:") and each variable only has ONE prompt.
Often with only a slight change in the display prompt the statistician will prefer to keep the variable in the same column within the data set (option 1 below). This is done in study by either creating a second, non-exportable variable, that is only used for the display prompt and is shown/hidden when appropriate. Or the time reference is taken out of the prompt and put in a heading and the heading is shown/hidden when appropriate (e.g., one heading says, "The following question refer to in the past week", whereas the other heading says, "The following questions refer to since the last visit".
Other times, the statistician will prefer a completely new variable (option 2 below). There are pro's and con's as to how to handle such cases, but the general recommendation is to define as few of variables as possible using different display prompts so that everything lines up in the up in the dataset (see image belowOption 1).
What to Consider
- Review the meaning of Universal Subject Variables, Project Variables, and Encounter Variables.
- Universal Subject Variables
- Plan the variables that will be Universal Subject Variables. These variables are used across all projects. Subjects enrolled in subsequent projects will not need their universal subject variables re-entered. Individual projects can opt out of viewing any of the Universal Subject Variables.
- Project Variables
- It is recommended to use a discontinuation date in your project. This will keep subjects who are no longer actively participating in the project from showing up on the Subjects Due list and their Subject Overview page will indicate the subject is discontinued
- Encounter Variables
- A variable group that will be collected on multiple occurrences only needs to be created one time. The intervals determine the data collection schedule and the same variable group can be collected on multiple intervals.
- Variables
- When creating a variable, be sure the variable type is correct. The variable type cannot be changed once data is collected. A common error is to use a text type variable instead of a numeric type variable.
A minimum and maximum allowed value can be entered for numeric variables.
Tip Be sure to set up this validation before any data is entered as it can not be set up or tightened after data entry has started
- How can the data burden be minimized?
- Variable defaults
- Calculated variables
- Rather than setting up a text variable consider whether a pick-list can be used with one option being "Other". Selecting other can trigger a text box to display.
- Determine if any numeric or categorical variables need missing values defined
- Think about whether a variable should be not required or required. If required, should a value be mandatory for data entry?
- Variable Groups
- Plan what the form should look like
- Think about the design and layout options that best facilitate data entry
- If subjects will enter data, are there any special needs (e.g. sound, large fonts, etc.)?
- Use the Layout tab's Default Prompt Width and Default Answer Width to accomodate the majority of the variables' widths
- Before copying variables, verify the setup of the variable to be copied is correct to minimize changes
- The *Layout *tab of the Variable Group Update page can be used to customize the form (e.g., colors, layout of questions, adding images)
- Will there be a paper source? If so, will data be double data entered and which variables?
- Be sure to import and leverage existing forms already set up on your system and the StudyTRAX Sharing Forms site
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- Multi-media data entry with video, sounds, pictures, etc.
- Data entry forms with extensive validation routines (e.g. skip logic, etc.)
- Forms that integrate data entry with clicking on an image, or a form with a background image with data entry field positions designed accordingly
- Standard layouts with one variable per row
- Matrix type layout
- Table layouts
- Automatic scoring
See ExamplesSee Form Design for ideas on what can be done with forms.