Codebooks and crosswalks

The Variables Codebook

Each bill record is associated with a large number of variables related to its content, progress and sponsor. This codebook provides details on the variables made available through the download tool.

Despite this, there is a pretty good chance that a researcher will want a piece of information that we do not currently provide. Often, that information can be found with some creative manipulation of the provided information, but at other times, the researcher will have no choice but to supplement our data with data from other sources.

The Topics Codebook .

Our coding mirrors that of the Policy Agendas Project. We have assigned a single topic code to each bill. This allows researchers to study policy related trends and to filter bills of particular interest (such as those relating to education or the environment).

This coding system advantages over other indexing systems for certain purposes:

1) Trends in bill sponsorship activity can be compred to other forms of policymaking activity (hearings, laws, executive orders etc) documented as part of the Policy Agendas Project.

2) Other indexing systems (what we call "information retrieval systems") such as the Library of Congress' Legislative Indexing Vocabulary (LIV) are designed to assist contemporary researchers in finding potentially relevant legislation and cannot be used to reliably trace trends in policy activity across time. For more on this subject, see Studying Policy Dynamics

However, researchers should not assume that every bill relating to 'air pollution' (for example) will be found within our 705 subtopic category. A bill that is primarily about something else may get coded under a different subtopic. In addition, our topic assignments are based only on titles (or short descriptions for the pre-1973 period).

Please send us a note if you identify an obvious coding error. In our experience, blatant coding errors are rare but they do happen. The more likely event is that similar events will be assigned to different topics due to legitimate differences in judgment concerning the bill's primary topic. We seek to achieve 90% interannotator reliability at the major topic level, and 80% at the subtopic level but these percentages still vary by topic and coder.

Crosswalks

Committee Membership. The Policy Agendas committee codes we use are different from those used in the Committee membership database maintained by Professor Charles Stewart at MIT. This Committees Crosswalk facilitates efforts to integrate information from the two datasets.

ICPSR - NOMINATE crosswalk. The ICPSR numbers used in some other datasets are notoriously confusing. Two members may have the same ICPSR number, and the same member may have been assigned different numbers in different Congresses. Nevertheless, users may still want to integrate the valuable data contained in those datasets. This Member ID crosswalk can be used to associate old ICPSR numbers with the one used in the bills project - the revised member IDs developed by Keith Poole and Howard Rosenthal as part of the NOMINATE project.

Credits

Funding