SDR database v.2.0 (hereafter, SDR2) has harmonized information from 23 international survey projects (cf. Table 9.1) for 4,402,489 respondents interviewed across 3329 national surveys that, taken together, span the period 1966–2017 and 156 countries. SDR2 provides both target variables and methodological indicators that store source survey and ex-post harmonization metadata (see SDR at a glance). Researchers can access the SDR2 (in SPSS and STATA formats) and the full SDR2 documentation on Harvard Dataverse (Slomczynski, K.M; Tomescu-Dubrow, I; Wysmulek, I; Powałko, P; Jenkins, J. C; Ślarzyński, M; Zieliński, M W.; Skora, Z; Li, O; Lavryk, D 2023, “SDR2 Database”, 

Substantive target variables in the SDR database cover respondents’:

(1) socio-demographics;

(2) political engagement, including interest in politics, voting, and protest behavior;

(3) trust in political institutions;

(4) social capital (generalized social trust and membership in organizations);

(5) self-reported health, life satisfaction and happiness.

The SDR database spans the period 1966-2017 and includes information on a total of 169 countries/territories. It extends the SDR database v 1.0-1.1. that the NCN Harmonization Project produced.

SDR2 at a glance

Time span1966-2017
# countries156
# respondents4,402,489
# source survey projects23
# source project wavesa174
# source national surveys3,329
# source data filesa215
# source survey quality indicators38
# technical target variables9
# substantive target concepts30
# harmonization controls73

a The difference between the number of source project waves (174) and that of source data files (215) in SDR2 stems from the structure of the downloaded source data files. While generally a source data file includes all national surveys of a given project-wave, sometimes repositories provide separate files for each national survey of a project-wave, or one single data file for multiple project-waves.

The SDR2 data are also available in CSV format (with corresponding syntax for reading the files into STATA/SPSS) from the SDR Portal (, whose extraction utility offers the possibility to download them in full or customize data selection according to specific variables, survey projects, countries and years.