XLSForm If Statement: Examples for ODK, Kobo, SurveyCTO

An XLSForm if statement is if(condition, value_if_true, value_if_false), written in the calculation column of a calculate row. ODK, KoboToolbox and SurveyCTO all read it the same way, so every example on this page works on all three. Each example below compiles with pyxform and ODK Validate, the same check ODK Central runs when you upload a form.

Download example form (.xlsx)All seven examples in one XLSForm, one group each. Tested with pyxform and ODK Validate; free to reuse under CC BY 4.0.Download

What is the syntax of if() in XLSForm?

type	name	label	calculation
integer	age	How old is the respondent?
calculate	age_group		if(${age} >= 18, 'adult', 'child')
note	show_group	This respondent is classified as: ${age_group}

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Three rules cover most mistakes:

• Lowercase if. XPath function names are case-sensitive, so IF( fails.
• Exactly three arguments. There is no two-argument form. Use '' for "nothing" in the false position.
• No leading =. XLSForm is not an Excel formula. =if(...) is rejected.

Text values go in quotes ('adult'). Numbers do not (if(${age} >= 18, 1, 0)).

How do I combine conditions with AND and OR?

XLSForm uses and and or as operators between conditions, not as functions. This example comes from a common KoboToolbox forum question: a child is eligible when aged 6 or over and in grade 2.

type	name	label	calculation
integer	child_age	How old is the child?
select_one grade	grade	Which grade is the child in?
calculate	eligible		if(${child_age} >= 6 and ${grade} = '2', 'eligible', 'not_eligible')
note	show_eligible	Eligibility: ${eligible}

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list_name	name	label
grade	1	Grade 1
grade	2	Grade 2
grade	3	Grade 3

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Add parentheses when you mix and with or, so the form reads the way you mean it: (${a} = '1' or ${b} = '1') and ${age} >= 18.

The comparison operators are =, !=, <, <=, >, >=. A select_one answer is the choice's name, so ${grade} = '2' compares against the name column, not the label "Grade 2".

How do I write a nested if statement?

Put a second if() in the false position of the first. Each extra level adds one more outcome. This classifies a Food Consumption Score with WFP's standard cut-offs of 21 and 35:

type	name	label	calculation	constraint
integer	fcs	Food Consumption Score (0 to 112)		. >= 0 and . <= 112
calculate	fcs_group		if(${fcs} <= 21, 'poor', if(${fcs} <= 35, 'borderline', 'acceptable'))
note	show_fcs	Food consumption: ${fcs_group}

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Read nested ifs from the outside in: the first condition that is true wins. So order the checks from the lowest band to the highest (or the reverse), never mixed.

How do I use if() with a select_multiple question?

A select_multiple answer is a space-separated list of names, such as 1 4, so ${water_sources} = '4' is only true when nothing else was ticked. Use selected(question, 'name') instead:

type	name	label	calculation
select_multiple water_source	water_sources	Which water sources does the household use?
calculate	uses_unsafe		if(selected(${water_sources}, '3') or selected(${water_sources}, '4'), 1, 0)
note	show_unsafe	Uses an unsafe source (1 = yes): ${uses_unsafe}

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list_name	name	label
water_source	1	Piped water
water_source	2	Protected well
water_source	3	Unprotected well
water_source	4	Surface water (river or pond)
water_source	-96	Other

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To count how many options were ticked, use count-selected(${water_sources}) instead of chaining ifs.

How do I calculate a score with if()?

Each if() returns a number, so you can add them. This is the standard pattern for weighted scores and simple composite indices:

type	name	label	calculation
select_one yes_no	has_latrine	Does the household have a latrine?
select_one yes_no	has_soap	Is there soap at the handwashing place?
select_one yes_no	treats_water	Does the household treat its drinking water?
calculate	wash_score		if(${has_latrine} = '1', 2, 0) + if(${has_soap} = '1', 1, 0) + if(${treats_water} = '1', 1, 0)
note	show_wash	WASH score: ${wash_score} out of 4

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list_name	name	label
yes_no	1	Yes
yes_no	0	No

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This pattern is also safe with skipped questions. An unanswered question is empty, '' = '1' is false, and the if() returns 0. Adding raw answers (${a} + ${b}) gives a blank result as soon as one of them is empty. If you need raw numbers, wrap each one in coalesce(${a}, 0). The XLSForm calculations guide covers this in more detail.

Can I use if() to change question text?

Yes. Labels cannot contain logic, but they can show a calculate. Work the wording out in a calculate, then reference it:

type	name	label	calculation
text	member_name	What is the household member's name?
select_one sex	member_sex	What is ${member_name}'s sex?
calculate	pronoun		if(${member_sex} = '1', 'he', 'she')
select_one yes_no	in_school	Is ${pronoun} currently attending school?

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list_name	name	label
sex	1	Male
sex	2	Female
yes_no	1	Yes
yes_no	0	No

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Do I need if() in relevant and constraint columns?

Usually not. The relevant and constraint columns already expect a true/false condition, so write the condition directly: ${age} >= 18, not if(${age} >= 18, true(), false()). See skip logic in XLSForm for the relevant column.

if() earns its place in a constraint when the rule itself depends on another answer. Here the allowed maximum depends on the unit the enumerator picked. Inside a constraint, . means "this question's answer":

type	name	label	constraint	constraint_message
select_one duration_unit	preg_unit	Will you record the pregnancy duration in weeks or months?
integer	preg_duration	How long has she been pregnant?	if(${preg_unit} = '1', . <= 42, . <= 10)	Weeks must be 42 or less; months must be 10 or less.

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list_name	name	label
duration_unit	1	Weeks
duration_unit	2	Months

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More validation patterns are in the XLSForm constraint examples.

Common if() errors and how to fix them

These are the messages ODK Validate returns, which is what you see when ODK Central, KoboToolbox or the XLSForm converter rejects a form:

You wrote	Write instead	Error you will see
IF(...)	if(...)	cannot handle function 'IF'
AND(a, b)	a and b	cannot handle function 'AND'
if(cond, 'x')	if(cond, 'x', '')	Requires 3 arguments but 2 provided
=if(...)	if(...)	Bad node ... in expression
a <> b	a != b	Bad node ... in expression
${a} / ${b}	${a} div ${b}	Unexpected beginning of path
'Dr ' & ${name}	concat('Dr ', ${name})	Couldn't understand the expression
${q} = '4' on select_multiple	selected(${q}, '4')	No error, but the result is wrong

The last row is the dangerous one: the form compiles and the logic is silently wrong for every respondent who ticks more than one option. For other messages, see common XLSForm errors, or paste your form into the free XLSForm validator.

Does if() work the same in ODK, KoboToolbox and SurveyCTO?

Yes. All three use the ODK XPath function if(condition, value_if_true, value_if_false). What differs is where you type it:

Platform	Where the if() goes
ODK (XLSForm)	calculation column of a calculate row
KoboToolbox Formbuilder	Add a Calculate question, then type the expression in its calculation box
KoboToolbox (XLSForm upload)	Same as ODK
SurveyCTO	calculation column of a calculate field (skip logic goes in a column named relevance)

A form built with these examples moves between the three platforms without changes to its logic.

Why conditional logic belongs in the form

Every if() you run during the interview is a classification you never have to rebuild in Stata or R, and the enumerator sees the result while the respondent is still there. A note that shows "Eligibility: not_eligible" catches a mistyped age on the spot. A cleaning script finds the same mistake weeks later, when nobody can fix it.

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Next: XLSForm calculation examples →