In 1999, Robert Marzano and John Kendall led a team of researchers at Mid-Continent Research
for Education and Learning (McREL) to estimate how much time would be required to teach the
200 academic standards and 3,093 benchmarks in the McREL standards database. The
standards and benchmarks were compiled from national and state standards documents and
covered fourteen different subject areas. Marzano and Kendall’s team surveyed 350 practicing
teachers, asking each one to “estimate the amount of time (rounded to the nearest hour) it
would take to ‘adequately address’ the content in a representative sample of benchmarks from
the database” (Marzano & Kendall, 1999, p. 102). Based on the evidence they collected, they
concluded that “it would take 15,465 hours to cover all 3,093 benchmarks” (p. 104).
To accompany their estimate of the time required to teach all of the benchmarks, Marzano and
Kendall (1999) estimated how much instructional time is available to teachers across the K–12
educational interval. They concluded that, using the most optimistic scenarios, 9,042 hours
might be available for instruction during a students’ career in the United States K–12 education
system. Clearly, trying to teach 15,000 hours of content in 9,000 hours of instructional time is a
frustrating predicament.
The creation of the Common Core State Standards (CCSS) and the Next Generation Science
Standards (NGSS) presented an opportunity to alleviate this issue. However, multiple analyses
(for example, Marzano & Yanoski, 2015; Marzano, Yanoski, Hoegh, & Simms, 2013; Porter, McMaken, Hwang, & Yang, 2011) have revealed that the updated standards documents still articulate more content than is practical to teach in the instructional time available. Many
teachers recognize this dilemma and must therefore make several unenviable decisions: Do I
try to cover all the content in a cursory manner? Do I select specific aspects of the content and
teach those well, while deemphasizing (or ignoring) other aspects? How do I know which
aspects are most important? Problems such as the following often arise when teachers must
make these difficult decisions.
• Teachers who attempt to cover all the content are overwhelmed. This might mean that
they do not have time to clearly articulate appropriate learning goals, design rigorous
instructional activities, or closely assess and track students’ learning.
• Teachers who select specific aspects of the content to focus on are influenced by
inappropriate guidelines. This might mean that a teacher prioritizes only that content
which appears on a standardized test students are required to take at the end of the
year.
• Teachers who teach the same courses prioritize different aspects of the content. This
might mean that the content a student learns in a class is dependent on the teacher to
whom he or she is assigned.
To address these problems, a team of analysts at Marzano Research sought to identify—as
objectively as possible—a focused set of content for each K–12 grade level in English language
arts (ELA), mathematics, and science.
