Answers to Frequently Asked Questions

Where did the data come from?
You can learn more about the data sources here.
Why are some of the data so old?
The oldest data we use come from the National Research Council's 1995 study, Research-Doctorate Programs in the United States: Continuity and Change. There are no other noncommercial sources for the faculty quality and educational effectiveness assessments in the NRC study. The NRC is in the process of conducting a new study, the results of which are slated for release in 2008. You can learn more about the NRC's new study here.
Why are there no rankings for programs in my field?
The set of ranked fields consists of (1) the fields ranked by the National Research Council in the 1995 study, Research-Doctorate Programs in the United States: Continuity and Change, and (2) the largest fields from the Survey of Earned Doctorates. Some smaller fields were not included because there were not sufficient data available for programs in these fields.
Why is my program not listed?
There are several possible reasons that a program might not be listed:
  1. We do not rank all fields (some data are not available for all fields). Your program might be in one of the fields that is not ranked. See above.
  2. Your program may be too small. Programs that produced fewer than 3 PhDs between 2001 and 2005 are not ranked.
  3. Your program may have been grouped together with another program. For some institutions and fields we only have data by field rather than by program. For example, in some cases an applied mathematics program and a pure mathematics program would be grouped together and listed as a mathematics program. This type of aggregation can happen when we have Survey of Earned Doctorates data (which is by field) but no National Research Council data (which is by program).
Why don't you include universities outside the United States?
We would love to include information about universities in other countries. The main obstacle is the availability of data. If you know of a data set that we could use, please let us know about it.
Why is some information missing?
There are two main reasons for missing values:

  1. Survey nonresponse: Many of the data sets we are using are generated from surveys of institutions or doctoral students. When questions in the surveys are unanswered, we end up with missing data.
  2. Confidentiality measures: Some data sets (e.g., the Survey of Earned Doctorates) have values suppressed to protect the confidentiality of survey responders. No values from the SED are reported unless they come from at least 5 survey responses. When reporting sets of percentages that add up to 100, additional suppression is done to prevent one from deducing a suppressed value by subtracting the sum of the remaining values from 100.
How were missing values estimated?
You can learn more about our methods here.
How was this project funded?
You can learn more about our funding here.
Who runs phds.org?
phds.org is run by Geoff Davis. You can learn more about the history of phds.org here.
About the Graduate School Guide
The graduate school rankings on phds.org have been made possible by grants from The Alfred P. Sloan Foundation and The Burroughs Wellcome Fund. The Center for Science and the Media served as the fiscal sponsor for the project.