How do I set up the Smart Field? (Step 3)

Learn how to set up calculations by using the smart field.

TABLE OF CONTENTS

• 1. Setup
  • 1.1 Smart Field output - Numeric output
  • 1.2. Smart Field output – Text output
• 2. Video

1. Setup

The "Smart" input field is a very powerful tool for real-time calculations in the input form. Drag & Drop the smart field into your form and define its logic:

	The text that will be displayed on the screen for the item question is entered in the "Display label" field (e.g. 'BMI').
	The system automatically fills in the database label and it does not require any further attention.
	The "Export label" field is also automatically populated by the system. However, it is advisable to create unique export labels. When exporting data (e.g. via Excel or CSV), these labels appear as column headings.
	You have the option of entering a description. This text will appear in light grey below the input field.
	a) Select "Numeric output" for calculations with numeric output. b) Select "Text output" for logics that imply a text output.  ⭐ Good to know: When including single choice or dropdown fields in the smart field, the option label will be used in the "Text output" and the value in the "Numeric output" logics.

1.1 Smart Field output - numeric output

	a) Select "Numeric output" to perform calculations on number fields.  For configuring 5b) text outputs refer to section 1.2. Smart Field output – Text output.
	Count missing values as 0: If you select "yes" and any input field used in the formula is empty (no value entered), hidden due to form or field dependencies or is marked as unavailable, the formula will be calculated and this field will be assigned the value 0. Otherwise, the calculation will only be performed once a value has been entered and the formula is considered "complete".
	To define the formula you can use the available input fields, operators, functions, and any numeric values. ⭐️ Input fields list: Use any of the number or slider fields in this form, as well as any single-select or dropdown fields with numeric values. ⭐️ A conditional expression must always include both ? (if) and : (else). Example: If a “unit” field uses the option values 1 for grams (g) and 2 for milligrams (mg), and a user enters a value in a “result” field, you can convert the result into milligrams by applying the following syntax in a smart field: {{unit}} == 1 ? ({{result}} * 1000) : {{result}} This means: if unit is equal to g (value 1), multiply the result by 1000, else keep the result as it was entered.  Conditional operators (<, >, <=, >=, ==, !=, AND, OR) should only be used inside conditional statements (?, :).
	Create your formula by selecting the input fields, operators and functions you want to use. You can also enter any numeric value, of course.  ⚠️ However, make sure you use a full stop (.) as the decimal separator to ensure valid syntax. The example shows how to calculate body mass index (BMI).
	Clicking on "Check syntax" will take you to the "Syntax check" tab, where you can enter actual numbers into the relevant input fields to test the displayed syntax. ⭐️ All calculated numeric output values are rounded to two decimals if applicable.
	Remember to save your smart field by clicking "Update basic field information".

Best Practice

With psychological questionnaires in particular, it is common to calculate a quotient based on the responses provided. With our system, you can allocate values to your answer options (read more about this in the following article). You can carry out calculations using these values in the smart fields. In most cases, it is not desirable for subjects to see their quotients/scores in the questionnaire itself. For this purpose, we recommend mirroring these fields into the eCRF (visit events). Read more about this functionality in the following article: How do I set up a mirrored fields functionality?

	b) Select "Text output" to include text fields into your formula.
	The "Combine" function allows you to combine or concatenate the values of different input fields and/or direct text input. See what your results will look like in the Syntax tab.
	The "Map" function is useful for filtering input fields based on the entered value. First, select an input field to be mapped against defined values. Then, add one or more values to the input bucket that will be compared with the value entered into the defined input field. If multiple values are selected, separate them using a semicolon (";"). Finally, define the smart field output value that will be displayed if the value of the input field matches or does not match the input bucket value. In this example, if the "Short text" input field is left empty, the smart field will display "No disease", whereas if specific diseases are entered, the smart field will display "Disease". Another example would be displaying a region in the smart field based on entered postcodes (e.g. input field = postcode; entered value in eCRF/value of input bucket = 80798; smart field value in eCRF/value of output bucket = Bavaria).

2. Smart Field in data collection

A smart field behaves like any other field in the form: it appears in exports, is integrated with validation and notification workflows, and is tracked in the audit trail. However, it is not editable by users; instead, it auto-calculates once all required input values are present (or if “count missing values as 0” is enabled).

3. Video

How do I set up a numeric smart field?

The "Smart" input field is a very powerful tool for real-time calculations using numbers, slider, single choice and dropdown fields.

For example you may want to calculate a BMI (Body-Mass-Index) or sum up the replies of a questionnaire by assigning numeric values to the answer options in a single choice type of question.

When including single choice or dropdown fields in the smart field, the option label will be used in the "Text output" and the numeric value in the "Numeric output" logics.