2  Number and share of referendums and ballot dates

2.1 National referendums and ballot dates per decade

Figure 2.1 shows the number of national referendums per decade from 1790 until today. The number of referendums fluctuated at low levels in the 19th century. In the 20th century, it has increased steadily from around 50 in the decade from 1900 to 1909 to over 600 in the decade from 1990 to 1999. Since then, the number has decreased to a bit more than 400 per decade from 2010 to 2019. In total, 3061 referendums have been held worldwide since 1790.

In the second graph, we can also see that once we exclude Switzerland (CH) and Liechtenstein (LI) from the analysis, the number of referendums worldwide since 1790 is reduced to 2267. Nevertheless, the general trends are the same: Having omitted Switzerland and Liechtenstein, we see a peak at around 500 referendums in the 1990ies, with a bit of a decline since then.

Looking at ballot dates, the picture is more evened-out, but the general trends are similar. There is an increase to a peak of around 250 ballot dates in the decade from 1990 to 1999, with a small decrease for the decades afterwards. Excluding Switzerland and Liechtenstein, the pattern ist the same but the total number of ballot dates is reduced from 1608 to 1197.

Figure 2.1: Number of national referendums and ballot dates per decade since 1790

(a) Referendums

(b) Referendums (without CH & LI)

(c) Ballot dates

(d) Ballot dates (without CH & LI)

2.2 Number and share of countries holding referendums

The number of countries that held referendums at least once a decade has increased tenfold since 1900, from around ten in the 1900s to over one hundred from in the 1990s and 2000s (Figure 2.2). If we control for the number of countries worldwide (Beger 2021; Correlates of War Project 2017), we find that the highest share was in the 1950ies and the 1990ies, when around half of all countries worldwide held at least one referendum.

Figure 2.2: Number and share of countries holding referendums since 1900

(a) number of countries

(b) share of countries

2.3 Top-ten analysis

Looking at the top-ten countries with the most referendums, we see that Switzerland held by far the most referendums since 1900, followed by New Zealand and Liechtenstein. Looking at ballot dates, Switzerland is still the lone frontrunner, with Liechtenstein coming in second and New Zealand third. It becomes apparent from Figure 2.3, that only ten countries are responsible for half the referendums and a third of all ballot dates worldwide since 1900.

Figure 2.3: Top-ten countries since 1900

(a) by number of referendums

(b) by ballot dates

2.4 Population size and ballot dates per country

With regard to referendums, there has been an ongoing debate on whether countries with smaller populations hold referendums more often than countries with larger populations. In line with the findings of Anckar (2004) and Vatter (2000), the analysis in Figure 2.4 shows that there is no correlation between a country’s population size (data by The World Bank (2023)) and its number of ballot dates per decade. Without the exception of a few outliers, mainly from Switzerland and Liechtenstein, we don’t observe more referendums (y-axis) in countries with a small population (x-axis). In fact, even larger countries can have a relatively high number of referendums per decade, e.g. Egypt in the 1970s.

Figure 2.4: Number of referendums per decade by population size