Record of American Democracy, State Level MCD-Group Data for MD

The Record of American Democracy (ROAD) data provide election returns, socioeconomic summaries, and demographic details about the American public at unusually low levels of geographic aggregation. The NSF-supported ROAD project spans every state in the country from 1984 through 1990 (including some off-year elections). These data enable research on topics such as electoral behavior, the political characteristics of local community context, electoral geography, the role of minority groups in elections and legislative redistricting, split ticket voting and divided government, and elections under federalism.
<br /> <br /> Another set of files has added to these roughly 30-40 political variables an additional 3,725 variables merged from the 1990 United States Census for 47,327 aggregate units called MCD Groups. The MCD Group is a construct for purposes of this data collection. It is based on a merging of the electoral precincts and Census Minor Civil Divisions (MCDs). An MCD is about the size of a city or town. An MCD Group is smaller than or equal to a county and (except in California) is greater
than or equal to the size of an MCD. The MCD Group units completely tile the United States landmass. This particular study contains the files for the State Level MCD Group Data for the state of Maryland.
<br /> <br /> Documentation and frequently asked questions are available online at the <a href="http://www.hmdc.harvard.edu/ROAD/">ROAD Website</a>. A downloadable PDF codebook is also available in the files section of this study.<br /> <br />

美国民主记录（The Record of American Democracy, ROAD）数据集提供了美国民众在极低地理聚合层级下的选举结果、社会经济概况与人口统计细节。本项目由美国国家科学基金会（National Science Foundation, NSF）资助，覆盖1984年至1990年全美所有州的相关数据（含部分非大选年选举数据）。该数据集可支撑选举行为、地方社区环境的政治特征、选举地理学、少数群体在选举与立法重划选区中的作用、分裂选票投票与分立政府，以及联邦制下的选举等主题的研究。

另有一组文件在原有约30至40项政治变量的基础上，新增了从1990年美国人口普查中合并得到的3725项变量，对应47327个被称为“MCD组（MCD Groups）”的聚合单元。MCD组是为本数据集采集工作设计的聚合单元，由选举选区与人口普查次要民政分区（Minor Civil Divisions, MCDs）合并而来。单个MCD的规模大致相当于一座城市或城镇；MCD组的规模不大于县，且（除加利福尼亚州外）不小于单个MCD。所有MCD组单元完整覆盖美国陆地疆域。本数据集包含马里兰州的州级MCD组数据文件。

数据集文档与常见问题可通过ROAD官方网站（<a href="http://www.hmdc.harvard.edu/ROAD/">http://www.hmdc.harvard.edu/ROAD/</a>）在线查阅。本数据集的文件板块中还提供了可下载的PDF版代码手册。