Survey Control File

Survey Questions

This section explains the different question types that you can use in the PIEL Survey.

All question types require an action of the participant to allow them to advance to the next question. This interaction activates the "Next" button on the bottom right of the screen and activates the "Swipe" capability.

Essential features

There are some features that all questions need to have.

  • A unique question ID. This is an integer followed by the separator "|" to separate it from the question text. Start integers at 1. Question IDs are stored with participants’ responses and also determine the order questions are presented. Questions are asked in ascending order.
  • There must not be any missing numbers in the sequence.
  • The question text followed by a %TYPE question description. If there is no %TYPE description, the question will be regarded by default as a "list" question.
  • Allocated text for responses (with the exception of free text questions). There is technically no limit to the number of response options you can have per question, but you should consider the usability of the survey when deciding how many responses to include.

Note that the vertical bar "|" separates the different components of the control file fields, questions and responses. Do not use "|" at the beginning or end of a control file line or in the question text. You do not need any spaces before or after this separator. Also do not use the symbol “%” followed immediately by a letter in the question text.


This is the default setting when no %TYPE is specified. The response options for list questions are presented as buttons on the screen (see the image below). Each response is allocated one button.

As the question label and the responses can wrap text, the space taken by these buttons will vary depending on the length of the text. Surveys should be tested to make sure that the answers can be seen easily by participants. Longer text or providing many response options may require the participant to scroll to see all the choices.

1|Where did you hear about the PIEL Survey?|colleague|publication|internet search|other

One of the responses must be selected to move to the next question.


A checkbox is similar to the list question but allows for multiple responses to the one question.

4|What features do you most like about the PIEL Survey? (you can choose more than one). %TYPE checkbox|Ease of use|Accessibility|It's quick|It's intuitive|It's on my iDevice|Other

One or more of the responses must be selected to move to the next question.


A slider (see following image) goes from a minimum to a maximum value.

The slider question is a way of gathering a numeric decimal rating from 0 to 1. The participant can just touch the slider button to accept the default position or else slide it to any value.

This type of question works well if there is a continuous range of potential answers rather than specific point answers.

This type of question removes the issue of a participant having to decide between two discrete options. It is an intuitive type of question and can in many cases be used instead of a standard Likert scale.

The slider requires only a light fingertip touch on the nub to move.

1|What percent of your diet is green vegetables?? %TYPE slider|0%|100%

Note that the starting position of the slider is by default in the middle (a value of 0.5). This can be changed to left or right by using the "%OPTIONS" keyword followed by "left" or "right". For example, the following example sets the initial position to the left.

1|What percent of your diet is green vegetables? %TYPE slider %OPTIONS left|0%|100%

To move to the next question, the slider must be tapped or moved.


The text question allows the use to type a response to an open-ended question.

To create a text box (see following image), use %TYPE text.

10|What other features do you want in the PIEL Survey? %TYPE text

Tapping on the “Type answer here” text will activate the keyboard. The question text will be moved up by the keyboard so there remains room to type a response.

You can customize which type of keyboard displays for the participant by using the "%OPTIONS" keyword followed by one of the following words:

  • normal
  • number
  • decimal
  • email
  • url
  • phone

If not set in the survey file, the default is "normal". Setting a different keyboard type can make the type of data entry required more intuitive.

For example, the following line brings up a number keypad.

10|What age are you? %TYPE text %OPTIONS number

To move to the next question, the participant must tap in the text box to bring up the on-screen keyboard.

Branching questions

During a survey, questions are presented by default in ascending integer order. However, if a participant chooses a particular response option for a "list" question, the questions immediately following may not be relevant to them. Questions can be branched so participants are directed to a designated question or to the end of the survey. To direct them to a designated question, put %NEXT and the required question number after the response.

The question number after %NEXT must be greater than the current question number. For more complicated branching surveys, it may be necessary to repeat questions to allow branching in later questions to ask those same questions.

Note that you can't branch from any other type of question.

We suggest you pay particular attention to testing branching surveys. The complexity is hidden from the participant as long as you make sure the branching question flow is logical.

In the following example, if a respondent chooses “Other", the next question, Q2, could ask for more information, if not the next question will be Q3.

1|How did you hear about the PIEL Survey?|From a colleague %NEXT 3|Internet Search %NEXT 3|Advertisment %NEXT 3|Reading a review/blog %NEXT 3|In the Apple Store %NEXT 3|Other

%NEXT END specifies that the participant skips the rest of the survey and is taken to the end screen or exit message.

8|Will you use the PIEL Survey again? %TYPE list|Yes|No %NEXT END|Maybe

If a participant goes backwards in the survey, then chooses a different branch, the previous choices after the old branch choice will be deleted and the new answers saved. This will help avoid mistakes when it comes to analysis but it must be kept in mind that blank responses in the data file may be due to choice of branching.