About the data

  • List of fields and descriptions
  • Sources
  • Updating schedule
  • Notes for Researchers

Click on the below links for more details on Parline data fields:

List of Comparative fields: a web page that lists the fields that can be compared, visualized and exported through Parline’s Compare tool with direct hyperlinks to those pages. Currently, 80+ fields can be compared across all chambers and parliaments, with the possibility of more being added in the future.

Parline database: Glossary of terms: a PDF file that lists 1) the political systems used to classify countries in Parline and the electoral systems used to classify directly elected chambers, and 2) describes four main electoral systems applied to directly elected chambers in Parline (List proportional representation, Plurality/Majority, Mixed system, and Other systems) and their sub-categories.

Annotated list of fields (English only): an Excel file that contains a list of all data fields in Parline. It indicates where each field can be found on individual chamber pages (e.g. via Basic Info, Working Methods etc.), which are time-series, and the schedule of update for each field.

Data is predominately collected directly from national parliaments through a series of questionnaires and via the IPU’s regular correspondence with them.

However, there are some notable exceptions when other sources are used.

Data on direct elections are gathered or received from national election commissions (data for indirect elections and appointed chambers are gathered from respective parliaments/chambers). When data is not available from a national election commission, unofficial sources will be used and verified with the respective parliament. Sources of data on direct elections are always indicated within the “Elections results” section of chamber pages.









Data for PPP conversion factor is taken from the World Bank’s World Development Indicators database. It is used to convert local currency into PPP dollars to allow for international comparison of budgets and salaries and allowances of members.

Data on national population is taken from the United Nations’ World Population Prospects database and used to calculate the number of inhabitants per parliamentarian. The data may be retrospectively updated when the United Nations revises the data.


Various questionnaires have been employed to collect data for Parline over the years. Since the unveiling of the current Parline database in 2018, the Annual activities and Post-election questionnaires are the core tools used to update time-series data and information that is likely to change either annually or after an election.

See Questionnaires for parliaments.

Researchers interested in earlier questionnaires can contact parline@ipu.org for more information.

How historical data is processed in Parline

Different fields in Parline are updated according to different schedules. There is an important distinction between fields for which past values are stored in the database (known as “time-series fields”) and those for which past values are not stored (“non-time-series fields”).

About 35 percent of Parline fields are time-series. Past values for time-series fields can be viewed by clicking on the historical icon next to those fields in Parline. A pop-up box opens that displays the past values, and the month/year in which the value changed (i.e. 2019-10 indicates October 2019).

Time-series fields are updated based on the schedule documented in the Annotated list of fields. Some time-series fields change frequently (e.g. Number of women in parliament which appears in the Monthly ranking of women in parliament), whereas others are more stable, and are updated only if and when there is a change, e.g. a change to a country’s name.

Another set of fields with historical values relates to “Elections results”. A separate “Elections results” page is created each time an election/renewal takes place.

All other fields in Parline are ‘non-time series. When new information is received and entered into the database, past values for these fields are not retained. In principle, non-time-series fields are fields whose values do not change frequently. The impetus for change is often a Constitutional amendment. For example “Parliamentary term”, “Authority that designates the Speaker”, “Legislation adopted by parliament requires the assent of the Head of State” are all determined by a country’s Constitution. IPU updates these fields through regular scanning (looking out for new Constitutions) and inviting parliaments to review their information, on at least an annual basis, to report any required updates.

How fields are updated in Parline

With few exceptions, each of the 600+ data fields are updated at one of the following frequencies:

  • Every time there is a change
  • annually
  • after an election/renewal (fields are valid for the timespan of the legislature), or
  • every few years

Fields that refer to a specific calendar year are updated via the Annual activities questionnaire, which is sent to all parliaments in the first quarter of every year.

Information on Annual activities is gathered throughout the year. Parliaments submit data at various times, for instance, in conjunction with the release of a parliament’s own annual report.

Fields that typically change around the time of an election are updated via the Post-election questionnaire, which is sent to every chamber where an election or renewal has taken place. Between 50-80 chambers are renewed via direct or indirect elections each year. The timeliness of updates to election fields in Parline is contingent upon finalisation of official results in a country. “Election results” are the first fields to be updated, and those contained within the Post-election questionnaire are not made until after a new legislature convenes and committee assignments have been made.

The IPU makes every effort to encourage parliaments to respond to these questionnaires in a timely manner.

(1) The IPU makes every effort to ensure that the data provided by parliaments for Parline is timely, accurate and up-to-date. As the source of the data, parliaments remain ultimately responsible for the quality of the data that they provide.

(2) In some cases, data is received from parliaments sometime after a change actually took place. When this happens, the historical records are modified so that the data appears from the time of the change, not the time at which the change was reported. Even so, we try to limit retroactive changes to the extent possible. Due to the possible changes, researchers should always note the date they have extracted data from Parline.

(3) Data on budgets and member salaries/allowances are collected in local currency and then automatically calculated in PPP dollars to allow for international comparison. The figures in PPP dollars may be retrospectively updated based on periodic revisions of PPP conversion factors published by the World Bank, thus affecting past PPP calculations in Parline.

(4) Researchers should be sure to be aware of the schedule of update for each field. Two sets of fields with particular characteristics are described below.

Example 1: Number of women in parliament

Parline contains four data fields about the number of women in parliament:

  • (1) “Women directly elected/appointed” and (2) “Number of women after an election/renewal” on the Elections page. This data refers to the results of the election or renewal.
  • the number of women at the start of a new legislature (identified under (3) “Number of members, by age”) on the Basic Information page. This refers to the first sitting of the new legislature, which can sometimes be different from the number of women elected.
  • and the (4) “Current number of members: women”, also on the Basic Information page, which tracks changes that occur during a legislature. This is the primary metric in Parline for the number of women and is used in the Monthly ranking of women in parliament.

While all of the fields refer to the number of women in parliament -- the figures for each field may be different given that each data field refers to the situation at a different time.

Example 2: Age of parliamentarians

  • Data on the age of members of parliament is collected at the start of a legislature and is not updated again until after the next election/renewal. Thus, the age breakdown reflects a moment in time (the start of the legislature) and does not reflect the current situation.

(5) Elections: The IPU published the Chronicle of Parliamentary Elections between 1967 and 2010. An electronic version of the Chronicle was included in the version of the Parline database that existed between 1996 and 2018: http://archive.ipu.org/parline-e/parlinesearch.asp

In 2018, IPU began publishing election-related data in the new version of Parline (data.ipu.org). At that time, some adjustments were made to the data fields published in Parline on elections. Data on the last election held for each parliamentary chamber was migrated to the new version of Parline at data.ipu.org.

Data on earlier elections have not yet been migrated to data.ipu.org. The data on earlier elections remains available via the archived version of Parline at http://archive.ipu.org/parline-e/parlinesearch.asp.

Contact parline@ipu.org for any further questions or clarifications.