PPRL: Privacy Preserving Record Linkage (R package)

A toolbox for deterministic, probabilistic and privacy-preserving record linkage techniques. Combines the functionality of the "Merge ToolBox"  with current privacy-preserving techniques. 

Schnell, R. and D. Rukasz (2021): PPRL: Privacy Preserving Record Linkage. R package version 0.3.6. CRAN

Merge ToolBox (MTB) - Record Linkage Software

MTB is a record linkage and de-duplication program in Java. Features of MTB include probabilistic and distance-based linkage techniques. MTB is free for academic use only. MTB and a manual can be found at the

Download page

Schnell, R.; Bachteler, T. & Bender, S. (2004): A Toolbox for record linkage; in: Austrian Journal of Statistics 33 (1-2) 125-133.  [PDF]

Schnell, R.; Bachteler, T. & Reiher, J. (2005): MTB: Ein Record-Linkage-Programm für die empirische Sozialforschung; in: ZA-Information 56 93-103.  [PDF]


Questionnaire Development and Documentation System (QDDS)

QDDS is a program system that allows permanent electronic documentation of questionnaire development and the final state of the instrument.

Download page

Schnell, R. & Kreuter, F. (2001): Neue Software-Werkzeuge zur Dokumentation der Fragebogenentwicklung; in: ZA-Informationen 48 56-70. [PDF]

Hopt, O.; Schnell, R.; Stempfhuber, M. & Zwingenberger, A. (2009): QDDS - Documenting survey questionnaires throughout their lifecycle. Paper for the Fifth International Conference on e-Social Science, 24.06.-26.06.09, Cologne. [PDF]


A macro for linking self-generated identification codes with a record linkage program

The MTB-macro codes.xml allows automatic linkage of self-generated identification codes by the method described in

[1] Schnell, R.; Bachteler, T. & Reiher, J.: Improving the Use of Self-Generated Identification
Codes; in: Evaluation Review 34 (5) 391-418.

See readme.txt or the Appendix in [1] for more explanation.

DEFECT questionnaire

Mail questionnaire [PDF] used in the DEFECT projects (DEFECT I, DEFECT II)