The table below contains the basic elements of the Studytrax data definition and the defaults used if the Studytrax team assists with setup.
Attribute | What’s Needed | Default Used if no information provided |
|---|---|---|
Variable Name | Descriptive Name | |
Unique code (no spaces/special characters [underscore ok]) | ||
Variable Type | Numeric – What is the range (min / max)? Units? | No range, no unit |
Calculation - How calculated? What if missing some values? | All values required for a calculation | |
Text - How many characters needed?
| Unlimited for questions like "Describe", "Comments" | |
Date – What is acceptable range? | Any valid date can be entered | |
Document – How many files and how large? | ||
Picklist (Coded list of value/label pairs, such as 0 = Male, 1 = Female). - What are the values and labels for all options? - do you want values displayed for data entry? - Can more than one option be selected? | 0=No, 1=Yes Other lists would start with 0 and increment by 1 Values are not displayed Only one option can be selected | |
Other | Exportable – Can values be exported in dataset? | Exportable |
Missing Values – Will value/label pairs are defined as “Missing” (e.g., Missing = -9)? | No missing value definition set up if not specified | |
Required - Must a value be entered? | Yes |
A good data definition provides ALL the characteristics forms (questionnaires, CRFs) and associated variables. What is needed is good old "TLV".
| Stands For.. | Overview | |
|---|---|---|
T | Type of Variable | The most common types are dates, number, coded variables (e.g., 0 = No, 1 = Yes; Tell us if more than one option can be selected). |
L | Layout and Logic | Indicate the look and feel of the variable, and when it should be displayed (e.g., only show if subject is a male). |
V | Validation | Indicate the rules that govern the acceptable variable values (acceptable range, units) |
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Communicating
Use A Spreadsheet
Document your data definition using the spreadsheet here.
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Example Marked Up Form
L - Layout and Logic
Keep
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It Simple
One row per variable (other Forms should use the cleanest, simplest layout possible. Standard practice is to use one-row-per-variable (examples here) is standard practice.
Leverage Visual Validation
A form's spatial and visual layout can be it's most important validation (see examples here).
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Form | Skip logic / condition |
Pregnancy Test | Hide form for males |
Demographic Data | Show text box if ‘other’ is selected for Race |
Variable Standards and Defaults
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Attribute
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What’s Needed
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Our Default
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Variable Name
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Descriptive Name
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Unique code (no spaces/special characters [underscore ok])
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Variable Type
Numeric – What is the range (min / max)? Units?
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No range, no unit
Calculation - How calculated? What if missing some values?
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All values required for a calculation
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Text - How many characters needed?
- Text variables require a limit (can range from 1 to 255 characters)
- Memo variables do not have a limit
Unlimited for questions like Describe, Comments
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Date – What is acceptable range?
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Any valid date can be entered
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Document – How many files and how large?
Coded list (e.g., 0 = Male…)
· What are the values and labels for all options?
- do you want values displayed for data entry?
· Can more than one option be selected?
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0=No, 1=Yes
Other lists would start with 0 and increment by 1
Values are not displayed
Only one option can be selected
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Definition
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Export – Can values be exported in dataset?
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Exportable
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Missing Values – Will values be assigned as “Missing” (e.g., Missing = -9)?
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No missing value definition set up if not specified
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Required
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Must a value be entered?
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Example: Data Collection Forms Schedule
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