Why T-Sheets Work
Disclosure: I have no financial interest in T-System, Inc.
There is nothing particularly high-tech about a T-Sheet. A T-Sheet (designed by T-System, Inc.) is a particular design for a double-sided, single-page printed paper form used to chart patient visits. T-Sheets are extremely popular and have been widely adopted by emergency department and urgent care physicians.
Why do many physicians prefer using T-sheets to the more technologically advanced EHR solutions that they are increasingly being required to adopt?
There are of course many reasons. One is so basic — and is such a defining property of the paper form in general — that we tend not to even notice it: T-Sheets assign each category of data to a box of fixed size and fixed location on the page.
A second reason T-Sheets are popular is that each presenting problem (chest pain, abdominal pain, headache, and so forth) has its own customized T-Sheet template. But regardless of the specific problem and the specific data collected, the spatial layout of data categories is kept exactly the same.
Here is an example of the front side of a T-Sheet for an emergency department visit that I have redrawn and greatly simplified to emphasize its high-level spatial design.
Regardless of the reason for the emergency department visit (in this case, chest pain), the box on the top right has a fixed size and location. It is always set aside for the review of systems (ROS). Similarly, regardless of the reason for the visit, the box on the bottom right has a fixed size and location. It is set aside for the family history. And so forth.
This means that once I learn where each category of data is situated on the page, I can just glance at that box to retrieve the desired information. Its position doesn’t change depending on how much data is written in the boxes above or next to it. The information remains readily available when I’m viewing a different box. I don’t have to carry it in my head.
The locations become automatic after a while. I don’t have to read the box headings. And if I need to compare the current visit to a previous one, I can just place the two T-Sheets side-by-side and glance at the same location on the two sheets to find the comparable data.
In my last post, Computer-Centered versus User-Centered Design, we saw how the spatial arrangement of data allows us to solve certain problems visually with minimal cognitive effort. But even if our task is just to take in and organize a large amount of data, a fixed spatial arrangement is a very good design.
Humans are visual animals par excellence. The human visual system is very good at organizing objects in space. T-Sheets and similar paper forms work because they enable us to use our extraordinary visual and spatial processing abilities to make sense of abstract data, even though these abilities evolved to help us organize physical objects in the real world.
Despite its simplicity, the paper form — with every data category assigned to a fixed location on the page — is a powerful cognitive tool. By allowing us to use our perceptual visual system to organize and retrieve a large body of information, it leaves our finite cognitive resources available for patient issues.
This all may seem obvious. Unfortunately, many EHR designs did not go in this direction, only in part because of technical constraints. Instead, clinicians often are required to navigate to multiple screens in order to enter or view different categories of data, as in the example below:
Of course paper forms have their own problems — how do you record more information than fits in a particular box, bring historical information forward to the next encounter without laboriously re-entering it, read illegible handwriting, and so forth? But still, assigning each data category a fixed screen location is a good model. So in rethinking EHR design, one strategy is to retain fixed spatial location as a high-level design element, but improve the paper design by making it interactive.
We need interactive T-Sheets.
Humans Have Limited Working Memory
Rick Weinhaus MD practices clinical ophthalmology in the Boston area. He trained at Harvard Medical School, The Massachusetts Eye and Ear Infirmary, and the Neuroscience Unit of the Schepens Eye Research Institute. He writes on how to design simple, powerful, elegant user interfaces for electronic health records (EHRs) by applying our understanding of human perception and cognition. He welcomes your comments and thoughts on this post and on EHR usability issues.