Policy Agendas Project Data from Congressional Hearings

• Click here to download data: Herfindahl analyses (Excel 5.0; .04MB)
• See an example of Committee Jurisdictional Clarity for the 102nd Congress.
• See detailed analysis in Working Paper 2

I. Indices of Committee Jurisdictional Clarity.

We developed indicators of jurisdictional clarity based on the proportion of total legislative attention (the number of committee hearings) to a given issue across committees (for a measure of overlap) or the proportion of total committee attention across issues (for a measure of span).

Our measure shows a value of 1 in the case of perfect jurisdictional clarity and a value approaching 0 in the case of maximum theoretical overlap or span. Our measures are derived from the Herfindahl index, a measure used by economists to assess market concentration. For each issue, therefore, we can use a Herfindahl score to summarize the degree to which a single committee dominates (a high score) or shares authority with a large number of rivals (low score).

Similarly, for each committee, we can summarize the degree to which it focuses its attention on just a single issue (a high score) or spreads its attention across many topics (low score). Both span and overlap are measured in the same way. Span indicates the range of attention of any particular committee; overlap indicates the range of committees active for any particular issue.

The averages of the span and overlap scores provide measures of the overall clarity of the entire committee jurisdiction system, which we call the Indices of Jurisdictional Clarity. These indices are, in effect, the sums of the indices of span and the indices of overlap, divided by the maximum value possible for those sums. For any given committee, the maximum clarity score possible is 1, representing a situation where all its attention is focused on a single issue. Summing all the committee span scores and dividing by the number of committees (or, simply taking the average score) gives an overall indicator of the degree of span. Similarly, for any given issue, the maximum clarity score is 1, where a single committee has a monopoly of jurisdictional authority. Taking the average of the overlap scores (or, equivalently, summing all the overlap scores and dividing by the number of issues) therefore provides an indicator of overlap for the system as a whole.

The indices of jurisdictional clarity have been computed using all hearings, non-referral hearings, and referral hearings. They have also been computed using only hearings that were originally released for public record. Thus this file includes the following indices of jurisdictional clarity from 1948-1992:

• Jurisdictional overlap by year for all House hearings
• Jurisdictional overlap by year for House non-referral hearings

• Jurisdictional overlap by year for House referral hearings
• Jurisdictional overlap by year for House originally published hearings

• Jurisdictional overlap by year for all Senate hearings
• Jurisdictional overlap by year for Senate non-referral hearings

• Jurisdictional overlap by year for Senate referral hearings
• Jurisdictional overlap by year for Senate originally published hearings

• Jurisdictional span by year for all House hearings
• Jurisdictional span by year for House referral hearings
• Jurisdictional span by year for House originally published hearings

• Jurisdictional span by year for House non-referral hearings (not yet computed)

• Jurisdictional span by year for all Senate hearings
• Jurisdictional span by year for Senate referral hearings
• Jurisdictional span by year for Senate originally published hearings

• Jurisdictional span by year for Senate non-referral hearings (not yet computed)

II. Number of Hearings used to Calculate the Indices of Jurisdictional Clarity.

We have included the total number of hearings used to calculate the indices listed above. Total hearings for span and overlap are different; the number of hearings used to calculate span scores is lower because select committee hearings were excluded from the analysis. Data are included for all hearings, non-referral hearings, referral hearings, and originally published hearings for both the House and Senate from 1948 to 1992.

III. Number of Subtopics Considered by Committees (Measure of Issue Density).

We developed a measure issue density based on the total number of distinct subtopics considered by House and Senate committees in a given year. There are a total of 223 subtopics in our coding system (see topic index code book). When used as an independent variable, this measure helps explain the decline in jurisdictional clarity over the 46 years for which we have data. Like the rest of the data presented here, this measure has also been calculated using all hearings, non-referral hearings, referral hearings, and originally published hearings for both the House and the Senate.

Click here to download data : Herfindahl analyses (Excel 5.0; .04MB)