Gerhard Meisenberg kindly sent me the following paper, which I was unaware of, in which he and Richard Lynn estimated national IQs using a broader set of international achievement tests:
Meisenberg and Lynn, 2011. Intelligence: A Measure of Human Capital in Nations
To note, I disagree with their method of calibrating the regional African tests (i.e., MLA, PASEC, and SACMEDQ). For these regional tests, scores, which were based on a 500 point scale with a mean set to the regional average, need to be adjusted by finding countries which participated in both regional tests and the regular international tests (e.g., TIMSS). Lynn and Meisenberg individually calibrated the three surveys. But as only a couple of countries participated both in TIMSS/PISA and in MLA and SACMEDQ and none participated in both TIMSS/PISA and PASEC — IQ scores were used to adjust instead — this method was probably somewhat inaccurate. A superior method would have been to simultaneously calibrate scores across surveys as the countries overlapped. (Some of the countries which participated in SACMEDQ participated in MLA and some of those which participated in MLA participated in PASEC.) Doing so would have given 5 to 9 anchoring countries, depending on which set of international reference tests was chosen, and increased the accuracy of the estimates.
Regardless, the estimates are accurate enough for the purposes of interest and should effectively silence the many critics who claimed that Lynn’s (African) IQ estimates were grossly inaccurate.