scrutinized carefully, as such claims had been used to justify racial discrimination. The report also acknowledged problems with the racial categories used, as these categories are neither consistently applied, nor homogeneous (see also race and ethnicity in the United States). In the UK, some African groups have higher average educational attainment and standardized test scores than the overall population. In 2010–2011, white British pupils were 2.3% less likely to have gained 5 A*–C grades at GCSE than the national average, whereas the likelihood was 21.8% above average for those of Nigerian origin, 5.5% above average for those of Ghanaian origin, and 1.4% above average for those of Sierra Leonian origin. For the two other African ethnic groups on which data was available, the likelihood was 23.7% below average for those of Somali origin and 35.3% below average for those of Congolese origin. In 2014, Black-African pupils of 11 language groups were more likely to pass Key Stage 2 Maths 4+ in England than the national average. Overall, the average pass rate by ethnicity was 86.5% for white British (N = 395,787), whereas it was 85.6% for Black-Africans (N = 18,497). Nevertheless, several Black-African language groups, including Yoruba, Igbo, Hausa, Akan, Ga, Swahili, Edo, Ewe, Amharic speakers, and English-speaking Africans, each had an average pass rate above the white British average (total N = 9,314), with the Hausa, Igbo, Yoruba, and Amhara having averages above 90% (N = 2,071). In 2017–2018, the percentage of pupils getting a strong pass (grade 5 or above) in the English and maths GCSE (in Key Stage 4) was 42.7% for whites (N = 396,680) and 44.3% for Black-Africans (N = 18,358). Flynn effect and the closing gap During the 20th century, raw scores on IQ tests were rising; this score increase is known as the "Flynn effect," named after James R. Flynn. In the United States, the increase was continuous and approximately linear from the earliest years of testing to about 1998 when the gains stopped and some tests even showed decreasing test scores. For example, the average scores of black people on some IQ tests in 1995 were the same as the scores of white people in 1945. As one pair of academics phrased it, "the typical African American today probably has a slightly higher IQ than the grandparents of today's average white American." Flynn has argued that, given that these changes took place