Political science Disclosing lobby income increases election chances
Transparency pays off for politicians: a new study shows that members of parliament gain in trustworthiness if they disclose their lobbying income - even if it is very high.
02.12.2025, 09:01
SDA
For the study, a research team from the Universities of Basel, Geneva and Vienna conducted an experiment to test how politicians are perceived when they disclose or conceal their additional income. Ancillary income is remuneration for functions in organizations with which parliamentarians have a vested interest, as the University of Basel explained in a press release on Tuesday. Over 14,000 people from seven European countries took part in the experiment.
In the experiments, the researchers presented the participants with fictitious tweets from fictitious parliamentarians: some published their fringe benefits from their vested interests, while others resisted transparency with reference to privacy.
Trustworthy and electable
The results published in the European Journal of Political Research were very clear: Politicians who disclosed their additional income received significantly higher average scores for trustworthiness and electability.
Members of parliament without additional income scored best, but even parliamentarians with very high additional income - up to 1.5 times the income from their mandate - were rated better than those who did not disclose their income.
Switzerland is non-transparent according to the researcher
"Switzerland is one of the least transparent countries in Europe because it is not clear how much money members of parliament receive and from where," said study author Stefanie Bailer from the University of Basel, according to a press release on the study. Since 1985, Swiss parliamentarians have been obliged to declare their vested interests. However, they do not have to disclose how much money they receive in return.
In parliamentary debates, the argument is often used that citizens are not interested in transparency, according to Bailer. The study clearly refutes this assumption.
