What you enter
- Question counts by type
- Total matrix rows and ranking items
- Reading-text word counts
- Respondent age, language and sample size
- Paths and the share of respondents following each path
The engine calculates the duration from these values.
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Help & methodology
SurveyLength calculates the duration from typical answering times per question type and the characteristics of your sample.
Two distinct roles
What the engine does
- Calculates the estimated completion time
- Calculates the lower and upper estimates
- Applies respondent characteristics: age structure, language group, sample size
- Applies the survey structure: question types, matrix items, reading words, paths
- Returns the same result for the same input, every time
Every minute and second you see comes from here.
Key concepts
The estimated survey length
The aim of SurveyLength is to provide an estimation of the median length of an online questionnaire, based on typical answering times for different question types combined with several criteria describing your respondents and your questionnaire.
Lower and upper estimates
As it is very unlikely to get an estimate precise to the second, the lower and upper estimates around the estimated length indicate that in all probability, the length of your survey should range between these two estimates.
Number of respondents
The number of respondents influences not the average estimated length, but the lower and upper estimates around it. The more respondents, the smaller the time interval around the estimated length.
Age of the respondents
Answering speed differs between age groups, so the age structure of your sample is part of the calculation. By default each age category is set to 12.5%; adjust the repartition to the age structure you need for your study.
Survey paths
Many surveys contain filter questions, so some respondents answer more questions than others. A path is a defined number of questions respondents have to answer; you can describe up to 3 paths and the percentage of respondents following each one.
Language
The questionnaire language is one of the calculation criteria. The engine uses the language groups of the original model: English, Chinese, French/German, Japanese/Korean, Russian/Eastern Europe, Spanish/Italian.
Question types used by the engine
These are the categories of the SurveyLength calculation engine, with the definitions used by the model. Enter the counts that match your questionnaire.
Single closed-ended question
All types of questions where respondents have to choose one or several answers in a predefined set of answers.
Example
On a scale from 1 to 9, how satisfied are you with your purchase?
How SurveyLength interprets it
Counted once per question in the path.
Matrix (matrix table question)
Used when respondents have to answer several questions using the same answer scale.
Example
How satisfied were you with the following aspects of the service? (1 “not at all satisfied” to 5 “completely satisfied”) — Speed of resolution · Knowledge of representative · Solution offered · Friendliness of representative
How SurveyLength interprets it
You enter the total number of items/rows respondents must answer across all matrix tables — 4 in the example above, not 1.
Multiple choice question
A simple, closed-ended question type that lets respondents select one or multiple answers from a defined list of choices.
Example
Which of these brands do you know? Select all that apply.
How SurveyLength interprets it
Counted once per question. “Select all that apply” wording is classified here rather than as a single closed-ended question.
Open-ended question
A question that respondents have to answer by using (and writing) their own words.
Example
If you would like to add any further comments concerning our service, please use the field below.
How SurveyLength interprets it
Counted once per question. Verbatim and free-text fields are classified here.
Ranking question
A ranking question asks respondents to compare items to each other by placing them in order of preference (drag-and-drop ranking, click ranking).
Example
Rank these five features from the most to the least important to you.
How SurveyLength interprets it
Enter the total number of items to be ranked.
Reading text (pages with text only)
Sometimes respondents have to read a text before or instead of answering a question. To estimate how long respondents need to read a text, count the number of words the text contains.
Example
A concept description, scenario or instruction screen shown before the questions that follow.
How SurveyLength interprets it
Time is derived from the number of words, so you enter a word count. Answer options and scale labels of a normal question are not reading texts.
Personalized / custom question
Certain complex questions may necessitate more time to answer. For example, respondents may have to watch a short movie, read a long text first, make a complicated calculation, etc. It is difficult to estimate the time needed to answer such questions without knowing the question itself.
Example
A card-sort exercise, a max-diff task, or a 30-second video test.
How SurveyLength interprets it
Two inputs: how often respondents answer this (or a similar) question, and your best estimate of the time they will take. The duration you provide is used as-is by the engine.
Frequently asked questions
Privacy of the manual calculator
Below is what the current implementation actually does. We deliberately avoid claims we cannot guarantee today.
Put it into practice
Enter your question counts and audience characteristics in the calculator.