Data for labor market concentration using Lightcast (formerly Burning Glass Technologies)

Using the job vacancy data from Lightcast from 2007Q1 to 2021Q2 (2008 and 2009 data are not available), we measure labor market concentration by using the Herfindahl Hirschman Index (HHI) in labor markets defined by the occupation (6-digit SOC), commuting zone, and quarterly level. The HHI is calculated based on the share of vacancies of all the firms that post vacancies in that market. It is the sum of vacancies by a given firm in a given market and year-quarter divided by the total vacancies of all firms posted on the website in that market and year-quarter. Data includes information on year-quarter, 6-digit SOC, commuting Zone, lower bound HHI, and higher bound HHI.

本研究采用Lightcast提供的2007年第一季度至2021年第二季度的职位空缺数据（2008年与2009年数据缺失），以职业（6位标准职业分类代码，6-digit SOC）、通勤区（commuting zone）及季度维度划分的劳动力市场为分析单元，使用赫芬达尔-赫希曼指数（Herfindahl Hirschman Index, HHI）测算劳动力市场集中度。该指数的计算基于在该市场发布职位空缺的全部企业的空缺岗位占比，具体为某企业在特定市场与季度的职位空缺数之和，除以同期该市场内所有企业在该网站发布的总职位空缺数。本数据集包含年份-季度、6位标准职业分类代码、通勤区、赫芬达尔-赫希曼指数下限值与上限值等相关信息。