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How to: Use repeat groups

Repeat groups help collect data in scenarios whereby you are required to ask the same group of questions a number of times in order to collect the same information about multiple people or items. For more information on repeat groups, please take a look at this guide. In this documentation, we will demonstrate different methods of collecting household information, where the same group of questions are asked a number of times in order to collect the same data about multiple household members.

Note: The exported data for repeat groups comes in a variety of formats. Depending on the export form, data within repeat groups can make data analysis difficult. We recommend using repeat groups with care, and construct a collection methodology on the use of repeat data before doing a large scale data collection.

Using a Simple Repeat:

Assuming we want the name, gender and age of members in a household, the survey sheet in our XLSForm would look something like this:  

type name label repeat_count calculation
begin repeat hh_repeat
text name What is the name of the household member?
select_one gender gender What is the gender of the household member?
integer age What is the age of the household member?
end repeat hh_repeat

When using ODK Collect

Before this set of questions is asked or asked again, a pop-up window will ask if the user wishes to add (another) family member (i.e. group of questions). The pop-up will ask using the label given in the begin repeat field, in this case, the repeat field label is null as no label was included in the XLSForm:

As long as the user clicks Add Group, he or she can keep entering details for additional household members. As soon as he or she clicks Do Not Add, the survey continues (or, in this case, ends, since there are no additional questions).

Note: If you hit Add Group, some of questions in the repeat group are required and decided after the group is added that you don’t need the extra group of questions, you will have to fill in the extra group of required repeat questions to be able to submit the data.

When using Enketo webforms

In the repeat group section in an Enketo webform, there is + button below the set of questions in the repeat. If the user wishes to add (another) family member, he/she can click on it. As soon as the user clicks on this button, he/she continues adding additional household members.

Determine the number of repeat group iterations

Instead of an infinite number of repeat group iterations, we can determine how many times the questions in the repeat group will be asked using a repeat_count. In our survey above, where we are collecting the name, gender and age of member in a household, we will add a question before the repeat group of questions asking how many members the household has. We will also add two new columns: repeat_count and calculation. The repeat_count column will help us specify the number of times the group of questions will be asked. The calculation column, in this case, will help us understand the position in the number of repeats from the first member’s group of questions to the last, which will be discuss further below. Our updated survey sheet will look like this:

type name label repeat_count calculation
integer hh_number How many members live in this household?
begin repeat hh_repeat_2 Repeat Count ${hh_number}
calculate hh_pos position(..)
text name_2 What is the name of the household member?
select_one gender gender_2 What is the gender of the household member?
integer age_2 What is the age of the household member?
end repeat hh_repeat_2

We can make the survey look neater and easier to understand by adding a reference label ${hh_pos} in the question label, which will show the calculated member’s position. Our survey sheet will look like this:

type name label repeat_count calculation
integer hh_number How many members live in this household?
begin repeat hh_repeat_2 Repeat Count ${hh_number}
calculate hh_pos position(..)
text name_2 What is the name of household member # ${hh_pos}?
select_one gender gender_2 What is ${name_2}’s gender?
integer age_2 How old is ${name_2}?
end repeat hh_repeat_2

Using Indexed-repeat()

Indexed-repeat is a function that allows you to get information from a specific iteration of a repeat group and use in either in another area of the form or another repeat group.  In our example, we will capture names from the hh_repeat_3 repeat group and capture their corresponding age and gender from the otherdetails repeat group. Our updated survey sheet will look like this:

type name label repeat_count calculation
begin repeat hh_repeat_3 HH Member name
calculate name_pos position(..)
text name_3 What is the name of household member # ${name_pos}?
end repeat hh_repeat_3
begin repeat otherdetails HH Member ages count(${name_3})
calculate namefromearlier indexed-repeat(${name_3}, ${hh_repeat_3}, position(..))
select_one gender gender_3 What is ${namefromearlier}’s gender?                     
integer age_3 How old is ${namefromearlier}?
end repeat otherdetails

In this example, we will extract the name of a household member from the repeat group hh_repeat_3 using the indexed-repeat() function. The calculate function indexed-repeat(${name_3}, ${hh_repeat_3}, position(..)) extracts the name of the household member coinciding with the position in the repeat groups in ${hh_repeat_3} and ${otherdetails} . The repeat group otherdetails has the repeat count set as count(${name_3}), which is the number of household members collected in the hh_repeat_3 repeat group.

Nested repeat  

In this section, we will be adding a repeat group into another repeat group. In our case, we will restructure our example so that we will have two repeats, where the education repeat group is in household_repeat repeat group.

type name label count_repeat calculation
integer number How many members stay in this household
begin repeat household_repeat ${number}
calculate cal_pos position(..)
text name Name
integer age Age
select_one gender gender Gender of # ${name}
decimal weight Weight of #${name}
integer schools How many schools have you attended
begin repeat education ${schools}
calculate cal_pos1 position(..)
text school_name Name of school #${cal_pos1}
select_one level ed_level Enter level of education
end repeat education
end repeat household_repeat

       

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