For those studying war, insurgency, irregulars or terrorism ESOC will be extremely useful – and depending on your area of research, possibly invaluable – as a resource.
Small Wars Journal had this to say about ESOC:
.…ESOC identifies, compiles, and analyzes micro-level conflict data and information on insurgency, civil war, and other sources of politically motivated violence worldwide. ESOC was established in 2008 by practitioners and scholars concerned by the significant barriers and upfront costs that challenge efforts to conduct careful sub-national research on conflict. The ESOC website is designed to help overcome these obstacles and to empower the quality of research needed to inform better policy and enhance security and good governance around the world.
The ESOC team includes about forty researchers (current and former) and is led by six members: Eli Berman, James D. Fearon, Joseph H. Felter, David Laitin, Jacob N. Shapiro, and Jeremy M. Weinstein.
The website is organized by countries and research themes. The six country pages are: Afghanistan, Colombia, Iraq, Pakistan, the Philippines, and Vietnam. The content is structured according to five themes: Demographic/Socioeconomic, Geography, Infrastructure, Public Opinion, and Violence. The website currently hosts about 45 ESOC data files, over 35 ESOC peer-reviewed publications (with replication data), and ten working papers. The ESOC team has also posted links to many external data repositories and external readings that have proven useful for analysis. The website will be regularly updated with new micro-level conflict data and contextual information, as it is compiled and submitted by ESOC researchers.
One caution: based on my source who was one of the folks gathering data for part of this project, as with all quantitative method research, there are hidden qualitative decisions in who did the counting, how and by what yardstick. If you are drawing conclusions about big picture trends in insurgency or irregular warfare across periods of time you are good to go. If your research is sharply confined to a specific and narrowly defined historical case study (say one campaign, a battle, one district – whatever), then drill down into ESOC’s data and methodology to the granular level before drawing a conclusion vice your sources and data outside ESOC.