Frequently Asked Questions
About the Graduate School Guide
- Where did the data come from?
You can learn more about the data sources here.
- Why do some of the ranges of rankings on the site differ from
those from the NRC?
- There are two reasons. First, the NRC's ranking algorithm
contains elements of randomness, and we cannot replicate the random
numbers used by the NRC in all cases. Second, in some cases the NRC
combines multiple programs into one, while we keep them separate.
Because our data set has more programs, the resulting rankings are
- Why are some of the data several years old?
- Most of the data sources we use take several years to compile
and release their data. As of fall 2010, we are using the most
recent data sets available from the NRC and IPEDS. The 2008 Survey
of Graduate Students and Postdoctorates in Sciences and Engineering
recently became available, and we plan to update from the 2007
survey in early 2011. We also plan to update the Survey of Earned
Doctorates data to the 2008 data set at the same time.
- Why are there no rankings for programs in my field?
- We are only ranking programs in the fields ranked by the
National Research Council in their 2010 study.
- Why is my program not listed?
There are several possible reasons that a program might not be
- We do not have data for all fields (some data are not
available for all fields). Your program might be in one of
the fields that is not ranked.
- Your program may be too small. Programs that produced
fewer than 3 PhDs between 2005 and 2009 are not
- 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
- Why don't you include universities outside the United
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:
- 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.
- 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 was this project funded?
You can learn more about our funding here.