College 1 correlationeel
Qualitative research: study people in natural environment; holistic approach; interviews,
focus groups, text analysis.
Correlational research: quantitative; relationships between variables; causal study difficult.
Experimental research: researcher manipulation; experimental and control group:
randomization of respondents into groups; quantitative measures; suitable for causal
research.
Different types of data, for example:
customer satisfaction, political polls,
governmental statistics.
Data are generated in different ways:
incidentally (organic, ready make) and
purposively (designed, custom made).
We design a study and collect data to:
describe the social reality, study
(causal) relationships, generalize to the
target population.
Inferential goals: description, causation, prediction.
Survey modes: face-to-face (CAPI), mail, telephone (CATI), internet, mixed-mode.
CAPI computer assistant personal interview
CATI computer assistant telephone interview
Mixed-mode two out of four other modes are combined.
Differences between the modes: degree of interviewer involvement; degree of interaction
with the respondent; degree of privacy; channels of communication: visual, auditive;
technology use.
Types of mixed-mode design:
- One mode for some respondents, another mode for others (e.g. online survey with
mail component for those without internet).
- One mode for recruitment, another for survey administration (e.g. mail invitation for
an online survey).
- One mode for data collection, another for reminders, follow-up (e.g. telephone
reminders for an online survey).
- One mode for main part of the interview, another for some subset of answers (for
example sensitive items).
- One mode for one wave of the panel survey, another for others (e.g. first wave face-
to-face, following waves online to save costs).
Cross-sectional survey enquête die op één moment wordt afgenomen.
Panel survey interview respondents over time (content usually the same, but may differ).
- Advantages: we can assess within-person change & causality; we can disentangle
age, period, and cohort effects.
Cohort effect: bijvoorbeeld een jaarlaag, die in hetzelfde jaar gestart zijn.
, - Potential errors: attrition (drop-out or consecutive wave-nonresponse); panel
conditioning (learning effects).
Learning effects: bijvoorbeeld weten welk antwoord je altijd invult op
dezelfde vragenlijst.
Dekkingsfout/coverage error fout die optreedt
doordat een onvolledige lijst van de populatie gebruikt
wordt.
Steekproeffout/sampling error op basis van toeval
treedt er een groot verschil op tussen de parameter van
de populatie met de statistiek van de steekproef.
Nonrespons fout fout die optreedt doordat
geselecteerde proefpersonen deelname weigeren.
Reasons: technical difficulties; lack of
motivation/interest; lack of trust with sensitive
questions.
Unit-nonresponse people chosen for the sample refuse to cooperate with the
survey request entirely.
Item-nonresponse people chosen for the sample refuse to answer a certain
question of the survey.
Nonresponse bias systematic differences between respondents and non-respondents on
key study variables.
Adjustment error because of coverage and nonresponse, statistics based on respondents
may depart from those of target population:
- e.g. underrepresentation of some groups (urban response rates lower than rural
response; new households/new employers in the frame). Adjustment: “weighting” up
the underrepresented.
- e.g. nonresponse to some questions. Adjustment: imputation.
Measurement error occurs if respondents provide inaccurate answers due to: survey
mode effects; poor question wording; aspects of their behavior.
Processing error occurs between receiving response of the respondent and publishing
statistics. Examples: data entry mistakes, coding/recoding errors, errors with handling
confidential information, calculation errors.