We (www.mdlogix.com) have just been awarded funding from NIDA for below 2-year project ("A Tool for Network Research on HIV Among Drug Users"), and are looking for a PhD or postdoctoral level person with social network expertise interested in joining us fulltime.

I will be at Sunbelt meeting in Cancun if anybody would like to meet with me.

Allen Tien


Phase I focused on the problem of linking members of network samples in large or unbounded populations, such as drug abusers in communities (or members of large corporations).  A software program (“SocioMetrica LinkAlyzer”) that matches and merges records from egocentric nomination data to construct sociometric data (containing more information on links between population members) was created.  LinkAlyzer uses attributes such as gender, age, physical features, and behaviors to determine if different records represent the same actual person (for analysis and for intervention) or the same type of person (for making population inferences).  In Phase I the LinkAlyzer program was used to process a HIV drug abuse data set with 15,000 records and 100 million potential matches, generating a network model.  Analytic results based upon that model suggest that matching records on a range of characteristics that represent the same types of person is sufficient for inferences about social networks.  The public health value of LinkAlyzer is substantial, because while it is relatively easy and inexpensive to gather egocentric nomination data (there are many existing data sets of this type), it is more difficult and costly to obtain or generate sociometric data.  LinkAlyzer is a tool that enables users to more easily apply sociometric methods to egocentric data, increasing their capability to use network models to make population inferences and address public health or other problems.

Phase II will create and further validate a SocioMetrica package of applications.  Assessment interfaces and functions will be added to assist in gathering personal/egocentric data from subjects.  Under the General Public Licence, code for the estimation of an expanded set of social network measures will be implemented.  In this engineering process, a Common Data Model and platform will be created that makes it easier for social network researchers work with different programs and to implement their own network measures and algorithms.  Due to the computational demands of LinkAlyzer matching functions and estimating certain social network measures with large datasets, an Internet architecture is planned to provide users with optional (and highly secure) access to low-cost processing power from servers with large amounts of RAM and multiple CPUs.  This Web services architecture will also simplify the business of software distribution, maintenance, and user support, and will facilitate value-added multi-site project operations and management.  Iterative testing and validation will be done with consultants and potential customers using existing projects and data sets.  The Specific Aims of Phase II are:

      1.        To create, test, and validate user interfaces for directly gathering network data;

      2.        To further validate, extend, and refine LinkAlyzer operations;

      3.        To create a platform that will facilitate the development and use of network estimation functions;

      4.        To implement an Internet distributed client-server architecture;

      5.        To implement multi-site project and data management and reporting functions.


Allen Y. Tien, MD, MHS
President and Research Director
Medical Decision Logic, Inc.
724 Dulaney Valley Road, Suite 2
Towson, MD 21204


Clinical Associate Professor
Department of Psychiatry
West Virginia University
Morgantown, WV

web site address: http://www.mdlogix.com

tel: 410-828-8948 or 410-821-5618
fax: 410-828-8948