Manuals

Title Interruptions (BETA)
Vsebina

Interruption means that respondent has stopped with survey filling at certain point (breakoff).

In the normal data collection mode of application 1KA data is saved for each page. Only by enabling additional monitoring of paradata variables are saved promptly. In normal way of data collection breakoff means that all variables on certain page of a survey where breakoff occurred are left unanswered. If respondent had already answered to question (eg. QX1) on certain page of a survey and then left the survey, all questions on the page of question QX1 are left unanswered.

1KA generally marks unanswered questions – questions that were shown to respondent and were then not answered by the respondent – with value (-1). (-1) is a code for non-response of a variable. It means that a certain question was shown to the respondent and was left unanswered because of different reasons such as not knowing the answer or overlooking the question. In a case when respondent didn’t answer on any of the questions following the first unanswered question, all other answers are marked as a (-3). That means that a serial non – response happened and the responded did not answer on any of the following questions because of an interruption. In such cases most of the questions were not even shown to the respondent and therefore this is not a normal non-response, because survey was interrupted before a certain question was even shown to the respondent.

If a question is added subsequently, all respondents that had answered survey before that question was later added, are marked with (-4), except in the case of an interruption. In the case of interruption (-3) is assigned if that question is after the breakoff point. Respondent would not have answered to such a question anyway, because survey was interrupted before respondent has reached that question. If subsequently added question was before breakoff point, that question is marked with (-4) which means that that question was not answered by the respondent, because that question was not yet in a survey at the time of filling a survey.
 

Interruption on the level of a whole SURVEY are measured a percentage of units that have broken off survey in next ways:
 

1.Introduction breakoff rate – IBR

Introduction breakoff rate is a share of all units that have broken off after clicking on the introduction divided by all units that have started with questionnaire filling. Reasons for introduction breakoff are different. Some examples are characteristics of a survey (eg. sponsors), situational factors (time pressure) and specific characteristics of an invitation (eg. Frequency, time, content of introduction).

IBR= introduction breakoff/shown= (3) / shown
 

2. Questionnaire breakoff rate – QBR

Different causes are to blame for breakoffs later in the questionnaire. Some examples include circumstances in which respondent is at the moment (eg. Fatigue, disturbing factors ect.) and characteristics of a questionnaire (design, length, content, question types etc.). Questionnaire breakoff rate is calculated by dividing broken off units with all units that started survey.

QBR=breakoffs (shown – introductions breakoffs) = ((3) + (4) + (5)) / (shown-3))


3. Gross questionnaire breakoffs QBR´

We can also follow breakoffs of questionnaire among all units. We name this gross questionnaire breakoffs.

QBR' = QBR × (1 – IBR) = ((3) + (4) + (5)) / (shown – (3))  × ((3) / shown)
 

4. Total breakoff rate – TBR

Total breakoff rate expresses share of all introduction breakoffs and breakoffs of a questionnaire with all units that started with survey filling.

TBR= (introduction breakoff + questionnaire breakoff) / Shown
 

5. Retention rate

Opposite values of breakoff rates are named retention rates.

Retention rate = 1 – TBR = (1 – IBR) × (1 – QBR)

 

On the level of individual Items breakoffs are measured in the following ways:
 

1.Item breakoff rate – IBR

This rate expresses share of units that broke off in relation with all units that broke off or were exposed to the item.

IBR= breakoffs / (breakoffs + shown = breakoffs / (breakoffs + (valid + non response + non content)) = (-3) / ((-3) + (valid + (-1) + (-90, 91, ..99)))
 

2.Gross item breakoff rate – GBR

This rate expresses basic comulative share of units that broke off in relation to all non – empty units. Non – empty units are all units that answered at least one question. It is share of units that have status (-3) with answered item.

GBR= breakoffs / (all non – empty units) = breakoffs / (breakoffs + shown + skipped  + subsequent items = (-3) / ((-3) + (valid + (-1) + (-90, 91, ..99)) + (-2) + (-4)))
 

3.Net item breakoff rate – NBR

Net rates are based on net growth of breakoffs and not on comulatives of breakoffs such as IBR in GBR. NBR shows most accurately where breakoff happened. In this case we mark net growth in the number of breakoffs of question Qi as a difference in the relation with last question:

DELTA(Qi)= Breakoffs Q(i) – Breakoffs (Q(i-1) = (-3) Qi – (-3) Q(i-1)

NBR= DELTA/ (Breakoffs + Shown) =DELTA / (Breakoffs + (Valid + non response + non content))= DELTA/ ((-3)+(Valid+(-1)+(-90, 91, ..99)))


NBR marks relative growth of breakoffs at certain item and is relevant mostly for first variable on certain page. Net growth of breakoffs – number of units that broke off on the page of the survey where certain variable is located – is compared with number of units that this variable was shown to. 


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Edit date 27.07.2016
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