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Causal inference in Field Experiments


Entry requirements

  • Introduction to Research Methods and Statistics

  • Inferential Statistics

  • Experimental and Correlational Research (or similar courses)


An important part of the job of psychological research is discovering and explaining causal relationships. Randomised experiments form the best basis for causal inference, but experimental manipulation of the independent variable often cannot be realised for practical, ethical, or technical reasons. Therefore, causal relationships are often studied in field settings. Research in field settings varies in the amount of control that the researcher has over the study characteristics. There are true experiments in natural settings such as hospitals, schools, and factories. Other studies have a quasi-experimental design, with experimental groups, but without or with less control over assignment of research units to conditions. Alternatively, studies may be purely observational, without experimental interventions, but still set up in a systematic way that maximises the possibility of drawing causal conclusions (e.g. case-control-studies). In the course, we will give an overview of research designs and methods of data-analysis directed at drawing the best possible causal conclusions when the (experimental) conditions are less than ideal.

Course objectives

Students will be able to:

  • judge conclusions from field experiments on all relevant aspects of research validity;

  • propose an adequate research design, given the research question or hypothesis, to prevent of remove threats to research validity; and

  • apply adequate data analyses for estimating treatment effects in field experiments, e.g. correction with propensity scores.


For the timetables of your lectures, workgroups, and exams, select your study programme.
Psychology timetables

Lectures Work group sessions Exams



Students need to register for lectures, workgroups and exams.
Instructions for registration in courses for the 2nd and 3rd year


Elective students have to enroll for each course separately. For admission requirements contact your study advisor.

Exchange/Study abroad

For admission requirements, please contact your exchange coordinator.


Students are not automatically enrolled for an examination. They can register via uSis from 100 to 10 calendar days before the date; students who are not registered will not be permitted to take the examination.
Registering for exams

Mode of instruction

8 2-hour lectures and 8 2-hour compulsory work group sessions.
The work group sessions consist of case discussions, student presentations of validity threats in published empirical field studies, and data analysis for estimating treatment effects.
You should attend at least 6 of 8 workgroups.

Assessment method

A written examination assesses students’ theoretical and factual knowledge of causal inference in field experiments. This examination consists of multiple-choice and essay questions (weight: 60% of the final grade). A short written paper assesses the application of this knowledge to the validity of the conclusions of a published field study (weight: 40% of the final grade). Adequate active participation during the workgroups is an overall requirement for being awarded a final grade.

The Institute of Psychology uses fixed rules for grade calculation and compulsory attendance. It also follows the policy of the Faculty of Social and Behavioural Sciences to systematically check student papers for plagiarism with the help of software. Disciplinary measures will be taken when fraud is detected. Students are expected to be familiar with and understand the implications of these three policies.

Reading list

  • Rosenbaum, P. R. (2017). Observation and experiment. An introduction to causal inference. Cambridge (MA): Harvard University Press. ISBN: 9780674975576.

  • Additional papers to be announced on Blackboard..

Contact information

Dr. Peter de Heus