When a plane crashes, we examine every detail about the aircraft's mechanics. When a building collapses, we examine every detail about the building's construction. And when students fail to learn, we for some reason skip examining every detail about instructional design.
If an education system fails to ensure that every first grader can read the simple sentence "The name of the dog is Puppy," and every third grader can solve a two-digit subtraction problem such as 46 minus 17, then we must interrogate the details of reading and mathematics program design. The details of effective instructional design — just like building an aircraft — are too high stakes to be left to intuition, memory, or the whims of individual preference.
Direct Instruction (DI) is probably the most empirically validated type of structured pedagogy, its "purpose is to teach subject matter efficiently so that all the students learn all the material in the minimum amount of time." One of the many things I learned from studying DI programs was how textbooks include a pervasive flaw undermining efforts to solve the global learning crisis.
The flaw: a grocery list of goals
In a typical textbook, each learning goal is accompanied by a single lesson number. The table of contents looks something like: Lesson 1. Determine the sum of any two 1-digit numbers. Lesson 2. Write two facts as any two given 1-digit operations. And so on — 21 distinct learning goals, each visited once and never revisited.
After a year or two of classroom teaching, it became abundantly clear to me that to ensure what you teach 'sticks' with all kids, they need more than one lesson of practice. But simply extending the number of days on each goal is not precise enough either — that approach is still arbitrary.
There is also substantial research on spacing: long-term retention is improved when previously learned material is periodically revisited. The problem within most textbooks is that information from one chapter is seldom revisited in subsequent chapters.
What DI does differently
DI program scope and sequences fix this by ensuring each learning goal is practised over many lessons. Rather than devoting one lesson entirely to a single new goal, a DI lesson spreads practice across many goals — the majority of which are review of content already introduced.
The fix stated simply: most lessons should be mostly 'review.' This does not require more instructional time — it requires redesigning how time within each lesson is allocated.
This redesign produces two major benefits. First, students who struggle with a goal on day one have repeated opportunities to practise it. Second, students who understood on day one consolidate that understanding through spaced retrieval. Both groups learn more.
Why this matters
The stakes of getting instructional design right are highest in low and middle-income countries, where many children have only a year or two of effective schooling before circumstances pull them away. If the instructional materials delivered in those years are built on a flawed design, the opportunity is wasted.
Solving the global learning crisis requires taking the details of curriculum and lesson design as seriously as we take the details of building aircraft and bridges. The good news is that we know what the fix looks like. We just need to apply it.