The Tilburg Trust Experiment: A Dutch RCT Experiment with Social Assistance

Last registered on May 09, 2019


Trial Information

General Information

The Tilburg Trust Experiment: A Dutch RCT Experiment with Social Assistance
Initial registration date
April 24, 2019

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
April 29, 2019, 10:43 PM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
May 09, 2019, 10:40 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.



Primary Investigator

Tilburg University

Other Primary Investigator(s)

PI Affiliation
Tilburg University

Additional Trial Information

On going
Start date
End date
Secondary IDs
article 83 Participation Act
In the Netherlands the ineffectiveness of labor market reintegration policies within unemployment insurance and social welfare has led 6 Dutch municipalities (Tilburg, Wageningen, Groningen, Utrecht, Nijmegen and Deventer) to run RCT field experiments to test out new ways of implementing reintegration and income support policies. Among them is the city of Tilburg in which the local government in collaboration with societal organisations of social work and societal support have taken up the initiative already in 2015 to start the so-called Tilburg Trust Experiment. The RCT experiment got the approval of the Dutch Government which is required under the terms of the Participation Law (article 83) and eventually started in October 2017. The Tilburg experiment includes around 800 social assistance recipients. For the 2-year duration of the trial, the persons voluntarily participating in the experiment are randomly assigned to four treatment groups: 1: an exemption or self-management group combined with an additional work bonus for people entering fulltime work (earnings release), 2: a coaching group in which the persons get intensive supervision oriented at reinsertion into work also combined with an additional work bonus, 3: an intensive mediation group without earnings release, and eventually 4: a standard group for which nothing changed (they get the regular treatment). For methodological reasons a reference group is added as a fifth group to be able to compare the outcomes of the various treatments with the outcomes for people having any involvement in the experiment. The study is set up as a randomised controlled trial (RCT) with interventions running from half December 2017 to October, 1 in 2019. The primary outcome measure according to article 83 of the Participation Law is full-time reintegration into paid work. But the terms of law also mention secondary outcomes such as improvements in health and wellbeing, self-management capacities of people on social assistance, social participation and reduction of financial stress.
External Link(s)

Registration Citation

Muffels, Ruud and Jac van der Klink. 2019. "The Tilburg Trust Experiment: A Dutch RCT Experiment with Social Assistance." AEA RCT Registry. May 09.
Former Citation
Muffels, Ruud and Jac van der Klink. 2019. "The Tilburg Trust Experiment: A Dutch RCT Experiment with Social Assistance." AEA RCT Registry. May 09.
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Experimental Details


The Tilburg RCT experiment contains four treatment conditions, one control condition and a reference group.
- The three treatments are: (1) claimants are exempted from the standard obligations, such as applying for jobs, accepting job offers indicated by the municipality or joining reintegration programmes combined with an additional work bonus in the form of an extra earnings release option; (2) the coaching treatment combined with earnings release: participants receive intensive mediation support (5 contacts a year) through tailor-made supervision focused on reintegration into paid work or social participation activities when paid work is not yet feasible; (3) intensive tailor-made mediation (6 contacts a year) but without additional earnings release options.

Work bonus
According to article 83 the existing release conditions are relaxed: whereas the current conditions are that people may keep 25% of additionally earned income up to a maximum of 199 EUR/month for a maximum of six months, the experimental treatment conditions are that people may keep 50% of additionally earned income up to max. 202 EUR/month for the duration of the experiment, that is 24 months. Tilburg has put on top of this a work bonus of an extra 200 EURO/month when mediation in group 1 or 2 will lead to fulltime reintegration into paid work. Such a bonus that is paid out once a year may be rendered 2 times at a maximum.

- In the control condition, claimants are subject to the standard treatment of the municipality of Tilburg which is largely set - with some discretionary power at the side of the municipality - by the rules and regulation of the Dutch Participation Law as of January, 1, 2015. Social welfare in the Netherlands is a welfare benefit scheme of last resort (hence, with a means and work test) for people having no other means of existences. The social assistance scheme provides monthly income support to single persons and households at a minimum income level, that is 70% of the minimum wage for a single person. For couples and families with children there are different amounts. The monthly amount for a single person is 992 EUR. On top of that welfare claimants may be eligible for child, housing and healthcare allowances. Recipients have to comply with certain rules, such as writing application letters, applying to job vacancies indicated by the municipality or following skills or personal development programmes. Recipients that fail to comply with the rules may be sanctioned by freezing or cutting their monthly benefit payment. Beneficiaries may be exempted from these obligations in the case people are incapacitated to work or face severe health problems. Local governments (municipalities and regional councils) are charged with the task of executing the scheme.

- Additionally, for methodological reasons a reference group of randomly selected claimants is designed consisting of social assistance beneficiaries who have any involvement in the experiment. The outcomes for the three treatment groups will be compared with the outcomes for the standard group and this reference group.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Our primary outcome indicator concerns reintegration into fulltime and parttime paid work.
Primary Outcomes (explanation)
The reintegration into fulltime or parttime paid work will be measured using local municipality data and administrative micro-data from Statistics Netherlands.

Secondary Outcomes

Secondary Outcomes (end points)
Our secondary outcome indicators are (1) social participation and activation, (2) participants’ health and well-being (3) participants' self-reliance and self-management capacities (5) satisfaction with support (6) participants' capabilities and (7) participants' financial situation (earnings income, poverty, financial stress).
Secondary Outcomes (explanation)
Social participation and activation is measured through self-reported survey data (e.g. frequency of contacts with social network; hours of volunteer work). Participants’ self-reliance and self-management capacities and capability scores, satisfaction with support and health and well-being is measured using survey data on self-efficacy, capability list of questions, support evaluation, subjective health, mental health and subjective wellbeing but possibly also health data from Statistics Netherlands. Participants’ financial situation is measured using administrative data and self-reported survey data.

Experimental Design

Experimental Design
The experiment is a cooperation between the University of Tilburg and the Municipality of Tilburg. Participating welfare claimants are randomly assigned to the four different conditions described above (three treatments groups and one control group).The target population for the experiment consists of all welfare claimants in Tilburg, except for some exclusion groups (not speaking Dutch, fully disabled, 65 years and older, homeless people, living in institutions). The target population is randomized over the four groups (three treatments groups and one control group). After this randomized assignment procedure claimants were invited to participate for that specific treatment during an information and enrolment campaign. Later on each participant was invited for a talk with the case-worker in which the client became informed about his/her treatment group and what it means for the support provided during the two years of experimentation. In the meeting also final confirmation of participation is asked for. Participation had to be confirmed through informed consent. Participation is voluntary, which means that participants can decide to drop out or withdraw at any time.
Experimental Design Details
In total, 783 claimants have signed up to take part in the study after which 147 participants in the end withdrew. The net total number is 636 participants which makes up for around 10% of the targeted population. Data is collected using administrative data as well as three longitudinal surveys. Data collection takes place at three points of time: Oct – Nov 2017 (baseline), Oct - Nov 2018 (midline) and Aug – Sep 2019 (endline).
Randomization Method
After selection of the target group the randomization is conducted in office using a computer programme operating on State 14.1.
Randomization Unit
individuals (social assistance recipients)
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
800 persons without clustering
Sample size: planned number of observations
800 observations in 4 groups
Sample size (or number of clusters) by treatment arms
Sample size: planned number of clusters
Sample size: planned number of observations
planned 800; realised 783; 147 attrition/refusal/drop-outs; net number: 636
Treatment 1 (exemption group): 165 claimants; Treatment 2 (coaching group): 161 claimants; Treatment 3 (intensive mediation): 138 claimants; Control: 172 claimants.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
200 persons in each group; power 95%; alpha 5%; effect size 10%; p=0.20 (control); 0.30 (treatment); sd 0.25 (control); 0.35 (treatment)
Supporting Documents and Materials


Document Name
Document Type
Document Description
Welfare States’ Social Investment Strategies and the
Emergence of Dutch Experiments on a Minimum Income
L o e k G r o o t ∗, Ru u d M u ff e l s ∗∗ a n d T i m o Ve r l a a t ∗∗∗
Social Policy & Society (2019) 18:2, 277–287, Cambridge University Press 2018 doi:10.1017/S1474746418000283

The focus in welfare state support in the Netherlands has been shifted from workfare and activation policies to social investment strategies. The discourse on basic income and the related municipal experiments highlights this shift. We address the inspiration found in basic income and behavioural economic and motivational psychological theoretical insights for the design of the experiments and for new avenues of minimum income protection and providing participation opportunities for the disadvantaged. The emerging new paradigm also implies a shift in the cultural values and principles on which welfare state policies are implicitly founded. This means that in these endeavours particular social values are put more upfront, such as personal autonomy (capacitating people by providing opportunities and therewith ‘free choice’) and trust (activating people by putting trust in their self-management capacities) which in day-to-day policy practice means more tailor-made, demand-oriented integrated mediation and coaching while rewarding people instead of penalising them.

MD5: 6da0e08b7745e5ffe4424c3b5c011720

SHA1: 59c8696c184edbb9b33d56f16f6361e1f2dc42f7

Uploaded At: April 24, 2019

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Institutional Review Boards (IRBs)

IRB Name
Ethics Review Board Tilburg University
IRB Approval Date
IRB Approval Number
N/A (EC 2016.52)
Analysis Plan

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Post Trial Information

Study Withdrawal

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Is the intervention completed?
Data Collection Complete
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials