Drawing from a large dataset of the characteristics of historical constitutions, scholars at the Comparative Constitutions Project have developed a set of indices that describe the content of world constitutions. Here we describe the constituent elements of each index and provide references for further reading.
Scope. This is drawn from Elkins, Ginsburg, and Melton, The Endurance of National Constitutions (Cambridge University Press, 2009). It measures the percentage of 70* major topics from the Comparative Constitutions Project (CCP) coding survey that are included in any given constitution.
Length (in Words). This is simply a report of the total number of words in the constitution as measured by Microsoft Word.
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Executive Power. This is an additive index drawn from a working paper, Constitutional Constraints on Executive Lawmaking. The index ranges from 0-7 and captures the presence or absence of seven important aspects of executive lawmaking: (1) the power to initiate legislation; (2) the power to issue decrees; (3) the power to initiate constitutional amendments; (4) the power to declare states of emergency; (5) veto power; (6) the power to challenge the constitutionality of legislation; and (7) the power to dissolve the legislature. The index score indicates the total number of these powers given to any national executive (president, prime minister, or assigned to the government) as a whole.
Legislative Power. This captures the formal degree of power assigned to the legislature by the constitution. The indicator is drawn from Elkins, Ginsburg, and Melton, The Endurance of National Constitutions (Cambridge University Press, 2009), in which we created a set of binary CCP variables to match the 32-item survey developed by M. Steven Fish and Mathew Kroenig in The Handbook of National Legislatures: A Global Survey (Cambridge University Press, 2009). The index score is simply the mean of the 32 binary elements, with higher numbers indicating more legislative power and lower numbers indicating less legislative power.
See how judicial independence and power have shifted over time in constitutions across the world here
Judicial Independence. The judicial independence index is drawn from a paper by Ginsburg and Melton, Does De Jure Judicial Independence Really Matter? A Reevaluation of Explanations for Judicial Independence. It is an additive index ranging from 0-6 that captures the constitutional presence or absence of six features thought to enhance judicial independence. The six features are: (1) whether the constitution contains an explicit statement of judicial independence; (2) whether the constitution provides that judges have lifetime appointments; (3) whether appointments to the highest court involve either a judicial council or two (or more) actors; (4) whether removal is prohibited or limited so that it requires the proposal of a supermajority vote in the legislature, or if only the public or judicial council can propose removal and another political actor is required to approve such a proposal; (5) whether removal is explicitly limited to crimes and other issues of misconduct, treason, or violations of the constitution; and (6) whether judicial salaries are protected from reduction.
Judicial Power. We also construct a six-feature index of judicial powers. The six features are: (1) whether the constitution provides for judicial review; (2) whether courts have the power to supervise elections; (3) whether any court has the power to declare political parties unconstitutional; (4) whether judges play a role in removing the executive, for example in impeachment; (5) whether any court has any ability to review declarations of emergency; and (6) whether any court has the power to review treaties.
Learn more about the proliferation of constitutional rights throughout time and across countries in our Data Story here
Number of Rights. This index is drawn from several articles in which Elkins, Ginsburg, and Melton analyze a set of 117** different rights found in national constitutions***. The rights index indicates the number of these rights found in any particular constitution.
Detail. This is also drawn from Elkins, Ginsburg, and Melton, The Endurance of National Constitutions (Cambridge University Press, 2009). It measures the average number of words per topic in the constitution; it is calculated by dividing Length (see above) by the number of topics captured in Scope.
Words About Rights. The CCP survey asks about the number of words in the rights section of the constitution, as measured by Microsoft Word. If rights are not included in a separate section, the measure is approximate.
*For a full list of variables used in the scope index, see Table A.2 of The Endurance of National Constitutions (Cambridge University Press, 2009).
**See the full list of variables in the rights index here.
***For example, “Imagining a World without the Universal Declaration of Human Rights.” Forthcoming, World Politics.