Description of iLEE – Københavns Universitet

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Centre for Experimental Economics > iLEE - Internet laboratory > Description of iLEE

Description of iLEE

"We bring the lab to your living room"

iLEE serves to conduct controlled experiments with participants from all walks of life from the Danish population. Controlled laboratory experiments have been used with much success in economics to investigate a wide range of economic choices. They allow to infer causal effects and motives for particular choices which is often fraught with difficulties if not impossible in the field. Such controlled experiments have traditionally been conducted in an experimental laboratory and with undergraduate students. Because iLEE uses a "virtual lab" approach, it enables us to conduct controlled and incentivized experiments over the internet and our collaboration with Statistics Denmark allows us to recruit people from all walks of life about whom we have very detailed statistical information from official registers.

Four waves

To date, four waves of the iLEE project have been completed. Each wave of the panel consists of several "modules" which can be an incentivized an interactive experiment, a preference elicitation task or a non-incentivized questionnaire. In general, the modules within a wave are independent of each other and our software allows us to randomize the order in which the participants go through the modules.

Each wave consists of paid and unpaid parts ("modules"). Participants were paid if they completed the entire wave and if they indicated a valid bank account. Earnings depend on the decisions made by the participants. Average earnings were around 300 kr. per participant and wave.

Participants are anonymous and come from all walks of life

Participants in the iLEE project were randomly selected from the Danish population aged 18-80. Participants were invited in a hard-copy letter from Statistcs Denmark. They were asked to log into a University webpage using an ID-number generated by Statics Denmark. In all waves, participants are matched with each other in some of the modules. Participants are fully anonymous to us and to each other. Participants of earlier waves are reinvited for later waves. This panel structure allows us to study behavior of people across a broad range of situations.

We started out recruting a random sample of the Danish population. While our samples in the specific modules are highly heterogenous, they are not fully representative of the Danish population in all dimensions due to attrition (i.e. our sample is not a rolling panel). In particular, about 2300 persons completed the first wave, but only about 700 completed the last wave. People in the age group 40-50 and those with higher education are over-represented but the sample is representative with respect to gender and geographical distribution.

We took great care to explain the experiments in plain and simple language to enable people from all walks to participate. We used graphical illustrations where appropriate (see examples below) and went through, in particular for the first wave, extensive pretesting to test procedures and subject understanding (e.g. in focus groups).

Description of the waves