- Disengaged or Very disengaged students are those with low sum scores and relatively short response times. Speeded or Very speeded students are those with low to medium sum scores and long response times at first but very short response times toward the end. Steady-paced students are those with medium to high sum scores and steady response times throughout the test. Efficient students are those with high sum scores and relatively short response times. Sample sizes are as follows: 618 in the USA, 242 in ENG, 1595 in the UAE, and 348 in SGP. Source: International Association for the Evaluation of Educational Achievement (IEA), Trends in International Mathematics and Science Study (TIMSS), 2019