See also the publications Voter Turnout Since 1945: A Global Report and Voter Turnout in Western Europe since 1945: A Regional Report, which are based on the data in this database.

What affects turnout?

A number of factors have been posited as having an impact upon how many people turn out to vote. These include institutional factors such as the type of electoral system used and whether voting is compulsory or not. Socio-economic factors such as the literacy rate, the wealth of a nation, its population size, and its "human development" level, and political factors such as the "competitiveness" of the system, have all been proposed as having a direct impact upon voter turnout. How do these claims stand up when tested empirically?

Institutional Factors
In line with the International IDEA Handbook of Electoral System Design (1997) we categorize electoral systems into three families: Plurality-Majority, Semi-Proportional (Semi-PR), and Proportional (PR). These are themselves divided into nine sub-families. First Past the Post (FPTP), the Block Vote (BV), the Alternative Vote (AV), and Two-Round Systems (TRS) are all Plurality-Majority systems. Parallel systems and the Single Non-Transferable Vote (SNTV) which are both Semi-PR systems. Finally, List PR, Mixed Member Proportional (MMP) and the Single Transferable Vote (STV) are all Proportional systems.

Figure 24
ELECTORAL SYSTEMS
ELECTORAL SYSTEMS
Key: VAP = voting age population
no. = number of elections
Figure 25
ELECTORAL SYSTEM FAMILIES
ELECTORAL SYSTEM FAMILIES
Key: VAP = voting age population
no. = number of elections

Figure 24 shows the average of each nation's most recent voter turnout categorized by electoral system type.
The two cases of STV, in Ireland and Malta, come out well ahead with a turnout rate of 83%, while Jordan and Vanuatu's SNTV systems have voter turnouts of only 54%. But the distribution of turnout among the three wider families of electoral systems appears to be largely random. A PR system comes first (STV), followed by a Plurality-Majority system (BV), then two more PR systems (List PR and MMP), and then another Plurality-Majority system (AV). But overall (see Figure 25) Plurality-Majority and Semi-PR systems only average 59-60% while straight PR systems average 68% turnout. This suggests that electoral system choice may have some impact upon overall turnout rates. Compulsory voting laws can also have an effect on overall turnout rates. Among established democracies, Australia, Belgium, Greece, Italy and Luxembourg all have some form of compulsory voting, as do many South and Central American states, although the extent and enforcement of these laws varies widely. A somewhat surprising result of this study is that the 24 nations which have some element of compulsion associated with voting have only a small lead in turnout over the 147 nations without any compulsory voting laws. One reason for this is that the turnout figures we use are based on the total voting age population, not just on the number of persons enrolled to vote - where the compulsory voting countries do have a marked advantage - so that the impact of compulsory voting may only be significant if registration rates are also high.

Figure 26
COMPULSORY VOTING
(last election only)
COMPULSORY VOTING (last election only)
Key: VAP = voting age population
no. = number of elections



Figure 27
TURNOUT FOR COUNTRIES WITH
LITERACY ABOVE AND BELOW 95%
TURNOUT FOR COUNTRIES WITH LITERACY ABOVE AND BELOW 95%
Key: VAP = voting age population
no. = number of elections

Socio-economic factors
There is no significant statistical correlation between a country's level of literacy and its voter turnout rate. However, the 52 states which have literacy levels above 95% clearly have a higher turnout rate (71%) compared to the 104 states with literacy rates below 95% (61%). These figures confirm that, while literacy is clearly an advantage, one should be careful not to equate issues concerning the ability to read and write with a voter's political literacy - i.e. the capacity to make coherent choices and decisions when voting - which are clearly not dependent upon formal education levels. We measure the wealth of a country by its Gross Domestic Product figure in US$ for the year of the election. Again there is no statistical correlation between this figure and the voter turnout rate. Similarly, the population size of a country seems to have little effect. As Figure 28 shows, countries with between 100,000 and one million inhabitants have the highest turnout rates and states with less than 100,000 people the lowest, but high and low turnout is almost equally distributed across large and small countries. In other words, there is no difference between rich and poor countries in terms of turnout, and no difference between small and large countries, a finding which may surprise those who assume that structural social explanations can be made for voter participation rates.

Figure 28
POPULATION SIZE
POPULATION SIZE
Key: VAP = voting age population
no. = number of elections

Indeed, the only socio-economic factor which does seem to correlate with turnout rates is the United Nation's somewhat more sophisticated "Human Development Index" (HDI). Turnout tracks closely a nation's level of Human Development. If we split the HDI league table into five equal sections we find that the top fifth of countries have an average voter turnout of 72%, the next 69%, the third 66%, the fourth 60%, and the bottom fifth an average of 56%.

Figure 29
HDI MOST RECENT ELECTIONS
IN THE IDEA DATABASE
HDI MOST RECENT ELECTIONS IN THE IDEA DATABASE
Key: VAP = voting age population
no. = number of elections

Finally, there does seem to be a clear link between voter turnout and the competitiveness of electoral politics in a political system. In the 542 elections where the largest party won less than half of the votes turnout was a full 10% higher than the 263 elections where a single party won over 50% of the popular vote.

Figure 30
COMPETITIVENESS OF THE SYSTEM
COMPETITIVENESS OF THE SYSTEM
Key: VAP = voting age population
no. = number of elections
 
Voter Turnout
 

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Voter Turnout per country: