PV Schaeffer. Data for the Policy Sciences (data_for_the_policy_sciences.pdf)	Description This is a list of data sources available free of charge on the internet. The document is in MS Word so that you can edit and update it to best meet your needs. It is updated several times a year, the last time on 11/21/2025. 28 pages. If you are new to applied research, please read the introduction before going to the data section.
Solutions to Problems in: Samuel Goldberg, 1958. Introduction to Difference Equations. John Wiley	Description This small book is well suited for self-study. The material is at the advanced undergraduate and master-level. While Goldberg's book contains the solutions to many of the problems, not all are covered and usually only the answer and not the process to obtain them is given. This solutions manual covers all problems and provides more detail.
Solutions to Problems in: John Hoag, 2008. Calculus and Techniques of Optimization with Microeconomic Applications World Scientific ​	Description This text is suitable for advanced undergraduate and masters students in economics. The answers in the solutions manual are specific and include many illustrations that may help in understanding and interpreting the results. This is a large file and will take some time to download. It is in MS Word format.
PV Schaeffer and K Willardsen. A Note on the Tinbergen Principle. Updated version of a paper presented at the Southern Regional Science Meeting in Washington, DC, April 4-6, 2019	Description Jan Tinbergen was an influential Dutch policy economist. In 1969, together with Ragnar Frisch, he was awarded the first Nobel Memorial Prize in Economics. The Tinbergen Principle is an important concept in economic policy that says that it requires at least as many policy tools as there are policy goals being pursued. This note could be used for self-study of this concept or could serve as a reading in a course on the theory of economic policy.