What is all about mile-wide-inch-deep curriculum?

Answer 1

A mile wide and an inch deep is a catchy slogan. This phrase is used to critique U.S. math education for having too many topics, as suggested by the TIMSS reports, with the implication that this factor results in poor achievement.

The prevalence of this interpretation gives the impression that the number of topics is a major cause of the poor showing of U.S. students, and therefore a reduction of the number of topics ought to be a high priority. Indeed, this idea may have become the main lesson learned from TIMSS.

How does the U.S. compare to "successful" countries?

Inspect the number of topics per year for Japan, Singapore, and the U.S. in the middle- and high-school grades and the difference isn't all that clear. Singapore is actually closer to the U.S. than to Japan in grades 7, 9, 10, 11 and 12. Yet, in grade 8 where the U.S. did so poorly, Singapore seems to have done just fine. The number of topics in Singapore actually exceeds that of the U.S. for grades 11 and 12.

What is the relationship of topic count to mean scores?

Compare the number of TIMSS topics in the 8th grade to scores on the 8th grade TIMSS statistically. The relationship is indeed negative, but only 3.1% of the variability of country mean scores can be accounted for by topic count. This is a rather small percentage to support inferences that will impact upon curriculum decisions.

A counter example

Not much lip-service is given to equation-related algebra when people talk about TIMSS findings. The proportion of the 8th grade text devoted to equation-related algebra is positively related to achievement. It accounts for 7.4% of the variance of country mean scores.