Rajyah Sabha chamber, Parliament of India

Table of contents

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The Inter-Parliamentary Union’s (IPU) Parline database provides monthly data about national parliaments. All information used in this fact file comes from the Parline August 2024 dataset unless otherwise stated. The IPU recognised 190 countries with national legislatures. Of these, 111 were unicameral (composed of a single parliamentary chamber) and 79 were bicameral (composed of two parliamentary chambers).

Figure 1. Number of unicameral vs bicameral legislatures

Bar chart showing that there were 111 unicameral legislatures and 79 bicameral legislatures.

1. Size of second chambers

At the time of writing, the House of Lords has 827 members, 801 of whom are eligible to attend proceedings. This is higher than all other second chambers: three out of four second chambers have a membership of 100 or fewer. The largest unicameral legislature in the world is China’s National People’s Congress, which has 2,977 members.

Figure 2. The membership of second chambers around the world

Donut chart showing that: 75% of second chambers had 100 members or fewer, 16% had 101 to 200 members and 9% had more than 200 members.

The House of Lords is also unusual in its size in relation to the lower house it is linked to, the House of Commons (which has 650 seats). According to the IPU, the House of Lords is the only upper house in the world that is larger than the lower house to which it is linked.

Figure 3. The size of second chambers compared with first chambers

Scatter plot showing that the House of Lords is the only second chamber to have more members than its partner chamber.

2. Membership terms

Many second chambers have a limit on the amount of time an individual can be elected or serve. In many cases these time limits apply through parliamentary terms, with a common term length being five years.

Figure 4. Length of membership terms in second chambers

Bar chart showing that most second chambers have membership terms of between four to six years.

3. Methods of selecting members

How members of a second chamber should be selected often features in discussions of House of Lords reform. Second chambers around the world offer a diverse range of examples of selection methods. These vary from wholly elected to wholly appointed chambers and those chambers that include a mixture of both. Figure 5 shows the principal ways members are selected in second chambers. In a quarter of second chambers the majority of members are appointed.

Figure 5. Principal methods of selecting members in second chambers

Donut chart showing that members are primarily appointed in 28% of second chambers, mostly directly elected in 36% of second chambers, and mainly indirectly elected in 36% of second chambers.

4. Data source

Cover image by Government of India on Wikimedia Commons.