Public Affairs

Incumbency advantage

Paul Redmond Paul Redmond explains how unfair advantages for office-holders prevent electoral change and may result in poorer politics.

A functional electoral system should act as a quality filter in which low quality candidates are “weeded out” and the highest quality candidates are successful. However, in reality, this may not be the case due to incumbent politicians possessing unfair advantages over challengers.

For example, incumbent politicians typically have access to state-paid travel, postage and telephones among other perquisites of office. The use of office-holder benefits to improve electoral prospects could result in the incumbent winning the election even if the challenger is of higher quality.

The Electoral Act 1997 imposes limits on the campaign expenditures of candidates seeking election in Ireland. However up until 2002, incumbent politicians were exempt from including certain office-related perquisites as declared expenses. This changed following the 2002 High Court ruling in the case of Kelly v The Minister for the Environment.

Desmond Kelly was a candidate seeking election to Dáil Éireann and was aggrieved that incumbents did not have to declare publicly funded office-holder benefits as election expenses. Kelly argued that it was “routine and common practice” for incumbents to take advantage of publicly funded services such as free postage, printing and telephones.

The High Court ultimately ruled in favour of Kelly which essentially limited the use of publicly funded expenses by incumbent politicians. However, this limit only applies to the short timeframe encompassing the election period and it could be argued that the real campaigning occurs throughout the inter-election period.

Inordinately high re-election rates may be an indication that incumbents possess an unfair advantage over challengers due to office-holder benefits. For example, US House incumbents are typically re-elected 90 per cent of the time. These high re-election rates sparked a huge interest in incumbency advantage in the US with some studies estimating that office-holder benefits increase an incumbent’s probability of running for and winning a subsequent election by 45 percentage points.

Like the US, the re-election rate of incumbent politicians in Ireland is one of the highest in the world. Apart from some notable exceptions (e.g. the 1997 and 2011 elections), the re-election rate of incumbent TDs typically stands above 80 per cent. Matland and Studlar (2004) compare re-election rates across 25 countries and find that Ireland has the fourth highest rate of incumbent re-election.

However, high re-election rates in themselves are not conclusive evidence of incumbency advantage. Even without office-holder benefits it is likely that an incumbent would be re-elected since she must be of high quality given her previous electoral success. However, the multi-dimensional aspects of candidate quality are difficult to quantify and measure and therefore it can be difficult to separate quality effects from office-holder benefits.

In joint work with John Regan (University College Dublin) we estimate the magnitude of the incumbency advantage in Irish elections using election data from 1937-2011. The methodology used allows us to separate incumbency advantage from quality effects. Our results point to significant office-holder benefits. We find that incumbency causes an 18 percentage point increase in the probability that a candidate runs for and wins a subsequent election in Dáil Éireann. We also find that incumbents receive approximately 1,200 more first preference votes and an extra 16 percentage point share of the quota compared to non-incumbent counterparts with comparable characteristics.

The implications of incumbency advantage are bleak. Low quality and under-performing politicians may not be replaced. In addition, potential high quality challengers may be dissuaded from even contesting the election if they feel their chances of success are too low.

Paul Redmond is a lecturer in economics in DIT Aungier Street and a research affiliate with

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