What does “reducing variance” mean in education?

I had great teachers and not so great teachers.  The funny thing is though, some of those on my “not so great” list were on other students “great” list.  How can that be?  I can’t help but think about this when I encounter terms like “reducing the variance” in education and wonder just how far the desire for sameness extends in to our classrooms – for students and teachers. It’s easy to see a business term like “reducing variance” applied to the business side of education.  How does it apply to teaching and learning?

A reasonably well constructed web search allowed me to learn that the Bibb County School District set about “reducing variance between school capacity and school enrollment” in its December 2007 redistricting plan.  I can understand wanting to do that.  Charlotte-Mecklenburg Schools studied their Transportation Services Operations.  They set out to “reduc(e) variance of planned versus actual route directions and time.”  I can understand them wanting to do that, too. 

An assistant superintendent I worked with in my early years talked about “learning being the constant while time is the variable.”  What are the variables and what are the constants in your educational environment?

When Marzano wrote of a “guaranteed and viable curriculum,” he viewed this school-level factor as “opportunity to learn” and “time”.  Was he writing about standards or standardization?  I found the abstract to this article “Reducing Content Variance and Improving Student Learning Outcomes: The Value of Standardization in a Multisection Course” and cringed at the title.  Standardization of what?  I am not willing to spend $32 to learn just how standardized the course was across the multiple sections, but the abstract seems to indicate the focus was curriculum.  Whew!

One of my all time favorite Grant Wiggins articles is Standards, Not Standardization: Evoking Quality Student Work. This article focuses on curriculum and assessment.  Is it possible to reduce the variance of curriculum and assess mastery while leaving day-to-day classroom level choices to the teachers?  I believe so.  Another of my favorite Wiggins articles is Teaching to the (Authentic) Test.  I appreciate ASCD making these oldies but goodies available for free to the general public.

How do we work to build a guaranteed and viable curriculum that is assessed in authentic ways while reducing the variance in outcomes (quality work) while we respond differently to student differences?  Teachers.  Great teachers who are supported in their work by administrators who understand that learning is a complex endeavor and requires a variety of resources are our best chance at ensuring no child is left behind.  Perhaps we can best reduce variance by introducing variance thoughtfully, though.

What would we choose to vary and why?  In the article “Mapping a Route Toward Differentiated Instruction,” Carol Tomlinson addresses several questions related to the topic of differentiation.  ASCD sign in is required to read the whole article, but the abstract may be enough to get you started!  In my years of reading her work and working with her on a number of projects in my district, Carol has engraved the words content, process, product, and environment in my brain.  If you are not familiar with Carol’s work and are interested in the question “what would we choose to vary and why?”, get familiar with it now. 

Reducing variance by introducing variance.  Sounds good to me!