By Larry Lesser
When I first started to teach (as a graduate student) in 1988, I began keeping files for each class I taught. The files contained organizational information specific to the institution, course, and textbook involved and included slides for particularly interesting activities or examples that I knew I would want to use again. As my teaching career unfolded (it has spanned three universities before my PhD and another three since my PhD), it became clear that it was not efficient to look for that cool statistics activity by going through files labeled STA 309, MAT 52-213, Math 20, BADM 34, Stat 150, Math 2200, Stat 1380, etc. (Even worse, my original filing system simply said "notes on Ch. 8," as if I would always teach or think in terms of that textbook I happened to use the first two years of my career.)
While struggling to keep up with one semester¹s particularly high teaching load (14 hours, four different preparations, including two new ones), I sought advice from my colleague Susan Ouzts. She kindly showed me how her file cabinets were full of materials (resource notes, camera-ready handouts or activity sheets, etc.) that were grouped by self-contained topics that could be quickly grabbed for a variety of classes. I adopted and adapted her idea and it has paid off. If I develop a neat lesson or activity on, say, the line of best fit, then a "line of best fit" folder with this activity is now ready to go whether I am teaching a college algebra course, a math modeling course, an introductory (or some other) statistics course, or some "math for teachers" course.
If I encounter a great clipping or graphical display in the newspaper that illustrates a commonly-taught mathematical or statistical topic, I can put the clipping in the file folder I already have on that topic rather than in some folder with a generic name like "clippings" which would be inefficient to search. Such files not only made it easier to teach these topics in a way that was more interactive and connected to the real-world, but also facilitated writing scholarly articles that connect a "broad net" of topics (e.g., ). This modular, topical filing system has also proven handy for quickly putting together talks on specific interesting topics for the local student math club or for local high schools.
I don¹t bother creating files for material that is common in textbooks, but rather I focus on particularly insightful metaphors or demonstrations (e.g., , ) or "beyond the book" connections to compelling but atypical realms (e.g., art, music, lottery, culture, ethics, social justice, etc.) that I want to have available for my teaching whether or not they are in the textbook I happen to be using. This naturally helps make my teaching more and more activity oriented as my repertoire grows. Another benefit is that by viewing what I teach in a modular, topical way, I am less tied to any particular textbook and therefore expend less time or emotional energy when a departmental committee decides to change a textbook or is charged with dissolving and reconfiguring a collection of courses to address credit hour mandates.
I have not completely abandoned my original by-course filing system, because it is still helpful to keep a skeletal file for each course with information such as the syllabus, exams, and grade sheet. But I have significantly reduced my class preparation time as well as time spent searching for items. And I have reduced the amount of paper I store because those activity sheets that once went into files for all the courses for which that activity was relevant or used now can be stored in just one file folder for that topic itself.
Time spent: minimal; a more-or-less one-time selection of key topics or applications that will have file folders created for them as you create and collect materials the first time you use them.
Time saved: roughly half of the time you spend preparing for any particular class which draws upon your collection of folders and the savings only seems to increase throughout your career.
 Lesser, L. M.; "Critical Values and Transforming Data: Teaching Statistics with Social Justice," Journal of Statistics Education, 15(1), March 2007, http://www.amstat.org/publications/jse/v15n1/lesser.html.
 Martin, M. A.; " 'It¹s like... you know': The Use of Analogies and Heuristics in Teaching Introductory Statistical Methods," Journal of Statistics Education, 11(2), July 2003, http://www.amstat.org/publications/jse/v11n2/martin.html.
 Sowey, E. R.; "Striking Demonstrations in Teaching Statistics," Journal of Statistics Education, 9(1), March 2001, http://www.amstat.org/publications/jse/v9n1/sowey.html.
Larry Lesser is an Associate Professor at The University of Texas at El Paso and his home page is http://www.math.utep.edu/Faculty/lesser/