Critically Thinking about the Bloom 2 Sigma Education Report

A MAJOR K-12 Education Matter...

This may sound like an egghead issue, but there are a LOT of new K-12 education ideas that are based on Bloom’s hypotheses — so what’s the scoop? [Note that this is a follow-up to my last commentary.]

Briefly, the story is that an educational psychologist named Benjamin Bloom published a report 40+ years ago about multiple different ways to possibly improve the effectiveness of teaching children. Here is his original report.

The widely proclaimed takeaway of his report is that one-on-one teaching is extremely effective. Bloom claimed that this effectiveness translated to producing a “two-sigma” improvement (a statistical term) in student learning — which (if true) would be significant.

What is a “two-sigma” improvement? This is a good explanation. A simple example is that it would make a “C” student an “A” student. Clearly, that would be a major improvement — thus the interest in Bloom’s report!

Based on Bloom, the biggest change currently being heavily promoted is to discard conventional classroom “direct instruction” pedagogy and instead teach children using Artificial Intelligence (AI). There are some undeniable benefits of this, but there are also some almost insurmountable problems. Here is a reasonably balanced discussion of both.

As a scientist, I’m disturbed by seeing a lot of material from education experts that is clearly not scientific. Further, I frequently see incomplete, inaccurate, or inappropriate conclusions drawn by educators from good studies. IMO, there is some of the latter going on here with Bloom’s work…

Some Observations and Concerns —

1 - In Bloom’s report, he experimented with about twenty education variables (including one-on-one tutoring). In this excellent discussion (that supports Bloom), it breaks down Bloom’s results from each of these research variables. It’s interesting to note that one variable (“Higher Mental Processes”) pertains to Critical Thinking. Note that it can also produce a 2 Sigma improvement! Why don’t we hear more about that?

“Certain schools in some countries (Bloom cites Israel, Malaysia, and South Korea) emphasize ‘problem-solving, application of principles, analytical skills, and creativity,’ {i.e., Critical Thinking} while schools in the US focus on specific content and ‘tests of remembered information.’ {See here!}

“Here’s a passage about how subjects are taught ‘as methods of inquiry’ in the first group of schools {i.e., non-US}:

“The subjects are taught as much for the ways of thinking they represent as for their traditional content. Much of this learning makes use of observations, reflections on these observations, experimentation with phenomena, and the use of first-hand data and daily experiences, as well as the use of primary printed sources.”

2 - There were two (2) key elements underlying Bloom’s conclusions: a) one-to-one tutoring, and b) students not moving on until there is mastery of the subject. The key question is: what degree of mastery is needed to move on?

This insightful discussion states that Bloom’s paper indicates that: “Classroom students were required to achieve a mastery threshold of 80% before advancing. Meanwhile, tutored students were required to achieve a threshold of 90%.”

Comparing two groups under different conditions is a scientific no-no. This is a major matter as subsequent studies revealed that: “students with a readiness above 90% achieved a 98% pass rate. But for those with a readiness score in the 81-90% range, the pass rate dropped to 69%.”

Here is more info on mastery learning… A reader’s very insightful observation: “Everyone’s been aiming for the wrong goal (replicating one-on-one tutoring), when perhaps a higher mastery threshold [before moving on] is the magic pill.”

3 - Although Bloom’s paper is used to claim that one-on-one tutoring is necessary, his actual research was with groups of three to five students, NOT just one-on-one. This is a major matter where one researcher observed:

“A private student can be continuously prodded during a lesson to focus and to strive, whereas a small-group student must practice and strive on their own in order to advance. In other words, the difference is initiative…”

4 - Bloom did NOT advocate computer learning, instead:

“In his paper, Bloom does mention computer learning courses, but he does not jump to the conclusion that we need technology to deliver cognitive tutoring experiences. Rather, Bloom proposes a different conclusion: we need to combine multiple learning interventions to achieve 2 sigma.”

“And most importantly, the learning interventions we choose need to be additive. For example, combining “Intervention A” (impact = 0.6 sigma) plus “Intervention B” (impact = 0.4 sigma) will not necessarily add up to 1 sigma. Instead, it might add up to only 0.8 sigma if both interventions take place in the classroom and their benefits overlap.”

I see very little discussion or application of this key Bloom information…

5 - In this detailed analysis (that supports Bloom), there is this extremely important, insightful observation:

“Artificial Intelligence (AI) models excel at drills, explanations, and pattern recognition but still struggle with teaching critical thinking, creativity, and deep conceptual understanding.”

This reality should give us extreme pause…

6 - Lastly, there are some more advanced technical issues with Bloom’s report. If you’d like to wade into those, then please carefully read: a) Bloom’s taxonomy is wrong—just ask Bloom! and b) Two-Sigma Tutoring: Separating Science Fiction from Science Fact.

Some Creative Conclusions —

As a scientist who is proudly an education “outsider,” I’ve not been impressed with the creativity being applied to the US K-12 public school system. One would think that the deplorable results (on all fronts) would mandate some imagination, but most creative ideas are immediately attacked with negative thinking. In other words, we prefer to keep digging the hole deeper.

Applying some Critical Thinking leads to non-conventional ideas like…

1 - We MUST come to an agreement as to what our NATIONAL K-12 education objectives are. There is no way that we can make meaningful K-12 system advances when we have fifty different mission statements (our current irrational predicament). In effect, we are trying to please everyone — like simultaneously aiming to accomplish equity and equality (an impossibility). The results we are getting are largely due to this insanity. The best and simplest solution to this crisis is to radically reform DOEd. Period.

2 - Starting in high school (and maybe junior high), separate boys from girls. Ideally this would be classes in different buildings, but at least on separate floors. A close reading of Bloom clearly concludes that when distractions are minimized, learning goes up for everyone. [Note 1: My high school was done this way, and it was a rousing success.]

3 - Have classes grouped by the performance of students. Bloom also clearly conveys that when a class is more homogeneous, teaching (and learning) can progress further and quicker. [Note 2: My high school was also done this way, and again it worked out very well… Note 3: There will be objections to points #2 and #3 here, but it all comes down to what our K-12 objectives are.]

4 - Accept that quality curricula are more important than effective teaching. (See this explained, and shown graphically.) In other words, students would be MUCH better off with a superior curriculum and inferior teaching than the reverse. This is a major matter not adequately covered by Bloom, although he does say, “We also needed to find ways of improving the curriculum…”

5 - Specifically train students to be Critical Thinkers. Although there is almost universal agreement that this is a desirable outcome (and it is specifically endorsed by Bloom’s 2 Sigma report), there is not a single State that is formally doing it! Again, this is where national leadership is needed.

The Bottom Line

There is a LOT of interesting educational information in Bloom’s report. However, almost all of the current applications of his work are just focused on the individual tutoring part — but ignore the serious qualifications about such tutoring. Further, Bloom’s multiple other conclusions about improving education outcomes are given short shrift.

IMO, those are both MAJOR mistakes.

——————————————————————————————————————

Some sample references —

Who Was Benjamin Bloom? A Deep Dive Into His Educational Legacy

The ‘2 Sigma Problem’ and EdTech: Scrutinizing the Evidence for Impact

Study Smarter: Fast, Effective Study with Bloom’s Taxonomy

On Bloom’s two sigma problem: A systematic review of the effectiveness of mastery learning, tutoring, and direct instruction

A Critical Appraisal of Bloom’s Taxonomy

Bloom’s Taxonomy (Explained in 3 Minutes)

The Problem with Bloom’s Two-Sigma Problem

Life and Legacy of Psychologist Benjamin Bloom

Mastery Learning

The case for direct instruction

The Effectiveness of Direct Instruction Curricula: A Meta-Analysis of a Half Century of Research

A Brief Summary of Research on Direct Instruction

Moving Students From Information Recitation to Information Understanding: Exploiting Bloom’s Taxonomy in Creating Science Questions

Study: Insights from early adopters of artificial intelligence in schools

---

Here is other information from this scientist that you might find interesting:

I am now offering incentives for you to sign up new subscribers!

I also consider reader submissions on Critical Thinking on my topics of interest.

My commentaries are my opinion about the material discussed therein, based on the information I have. If any readers have different information, please share it. If it is credible, I will be glad to reconsider my position.

Check out the Archives of this Critical Thinking substack.

C19Science.info is my one-page website that covers the lack of genuine Science behind our COVID-19 policies.

Election-Integrity.info is my one-page website that lists multiple major reports on the election integrity issue.

WiseEnergy.org is my multi-page website that discusses the Science (or lack thereof) behind our energy options.

Media Balance Newsletter: a free, twice-a-month newsletter that covers what the mainstream media does not do, on issues from climate to COVID, elections to education, renewables to religion, etc. Here are the Newsletter’s 2025 Archives. Please send me an email to get your free copy. When emailing me, please make sure to include your full name and the state where you live. (Of course, you can cancel the Media Balance Newsletter at any time - but why would you?

Thanks for reading Critically Thinking About Select Societal Issues! Please pass a link to this article on to other associates who might benefit. They can subscribe for FREE to receive new posts (typically about twice a week).