At the site I linked to, it said one could contact Tiffany Harrington tharrington@psychologicalscience.org to get a copy of the paper. She emailed it to me. The paragraph describing how national intelligence was measured is as follows (p9)
"Using results from TIMSS 1995-2007, PISA 2000-2006 and PIRLS 2001-2006, ability sum values for N=90 countries were calculated for the upper level (95th ability percentile, in within country norms IQ>125), the lower ability group (5th%, IQ<75) and
the mean (approx. 50th%, IQ≈100). The results of the different studies were aggregated in a stepwise manner and finally standardized on a common scale (UK: M=100, SD=15,
�Greenwich-IQ�; see the on-line supplement). The values could be expressed in different scales (IQ- or SAS-scale, student assessment score), the IQ-scale is better known, but does not imply any theory of ability differences (culture, education, genes, wealth, politics etc.). Nevertheless the student assessment tasks are good indicators of crystallized intelligence (and to some extent also of fluid intelligence, especially PISA
tasks) and there is a very strong G-factor which could explain between 82% (GDP partialed out) and 95% of cross-country variance in competence studies independent of scale (e.g. Verbal vs. Science Literacy), study (e.g. PISA vs. TIMSS), grade level (e.g.
4th vs. 8th grade) and paradigm (psychometric intelligence vs. student assessment; Rindermann, 2007)."
Two other papers by Rindermann are
Educational Policy and Cognitive Competences
Heiner Rindermann and Stephen J. Ceci
http://www.psychologicalscience.org/journals/pps/4_6_inpress/Rindermann_final.pdfThe g-Factor of International Cognitive Ability
Comparisons: The Homogeneity of Results in PISA,
TIMSS, PIRLS and IQ-Tests Across Nations
HEINER RINDERMANN
http://www.tu-chemnitz.de/hsw/psych...am/rindermann/publikationen/07EJPall.pdf The 2nd paper describes in detail how he estimates IQ across countries.
