Developing the “science of error measurement”

I woke up this morning to the People’s Pharmacy on NPR and an interview with Peter Pronovost (of checklist fame in a previous post) and David Newman-Toker. These two M.D.s hope to inspire research into accurate error measurement as an essential to developing systems that avoid errors in medical diagnosis. The goal of their commentary, published in JAMA, is to bring attention to the field of diagnosis.

The essence of the problem is that diagnosis errors are prevalent and not only result in ineffective treatment for a condition that is not present, but that either the lack of treatment of the real condition or the side-effects of treatment of the incorrectly diagnosed condition result in actual harm. This harm is one of the things that we do not yet measure well.

Once we fully understand the errors, we can develop effective decision aids that function and are accepted in the medical context.

How to reduce diagnostic errors (from the article):

  • Develop Systems Solutions to Cognitive Problems
  • Create Actionable Categories of Errors Based on Context Rather Than Cause
  • Emphasize Misdiagnosis-Related Harm Rather Than Diagnostic Error
  • Build Workflow-Sensitive Solutions
  • Focus on Comparative and Cost-effectiveness

Here are my favorite excerpts from the article that point to potential human factors solutions.

  • Look to other areas for information

“Parallels in medication safety offer an alternative view. If the problem is illegible physician handwriting in medical prescriptions, the most efficient solution is probably not handwriting retraining but computer-based prescription writing. Likewise, if the problem is a cognitive bias such as a tendency to overestimate the probability of a rare diagnosis recently encountered, the most efficient solution might not be cognitive debiasing training for all physicians but computer-based decision support systems that provide accurate estimates of disease probability.”

  • Collect data

“Systematically recording key clinical inputs (symptoms/signs/tests) and outputs (morbidity/mortality/costs) would also offer a platform for continuous quality improvement through structured feedback…”

Link to the primary source:

Newman-Toker, D.E. & Provanost, P. (2009). Diagnostic errors: The next frontier for patient safety. JAMA, 301 (10), 1060-1062.

HF/Usability Hodgepodge

Things too small for their own post but interesting nonetheless…it’s a hodgepodge, a mélange, a potpourri!

Two HF Driving News Articles

1. Although I had trouble finding corroborating sources, it looks as though the government of Samoa is going to switch what side of the road people drive on in a few weeks. You don’t have to be a human factors expert to guess at the trouble this will cause.

2. New study says older drivers are not “such a hazard.”

What I liked about this news article was that it intimated that AGE is not the problem, age-RELATED changes are. For example:

“Crash frequency increases at age 70 to 75,” she said. “But driving ability can be compromised at any age and by health conditions like diabetes, stroke or serious head injuries, so we have to have lots of built-in safety nets.”

Age-related specifies that these changes in vision, motor control, and cognition often accompany age, but there is high variability. It would be hard to argue that everyone loses their license at 75, for example, once you acknowledge that these changes are “age-related” instead of being due to aging.

The article also touched on selection, optimization, and compensation (SOC) that occurs for older drivers:

“As we get older,” he said, “our reaction times slow, our vision and peripheral vision decrease, our hearing decreases. But a person can compensate for all that with common sense. I know people in their 20s and 30s who I wouldn’t ride across the street with.”

If you’d like to learn more about the SOC model of adaptation, here is a free full text overview of the topic.

The data for these claims comes from the decline of fatal accidents for older drivers from 1997 to 2006. This graph comes from the Insurance Institute report.


Click here for a PDF of the primary source.

HF Potpourri

Some interesting items that have passed through my reader:

  • Jerk can be emulated in software.  Cars with continuously variable transmissions sound and behave differently from other cars.  In this video, the speedometer and RPM smoothly increases (in most cars the RPM would bobble as gears shift and you’d feel a slight jerk).  I don’t know how I reached this page but Wikipedia suggests that some companies may emulate “jerk” (what you feel when the car shifts gears) to make the car feel more normal to the driver.
  • Need a quick wireframe for your website? Try Hot Gloo, an online wireframe tool [hot gloo]
  • With the coming wave of web-based health management, how do patients feel about putting so much personal health data online? [Journal of Medical Internet Research]
  • Type is about to look very different on the web []

Fitts’ Law and Your Microwave

Most of you are familiar with Fitts’ Law and how it can be used to calculate movement time in an interface. You may even be familiar with how it ostensibly speeds up your use of menus on the Mac. But did you know it could improve your daily life? My friend Jeff Wilson did, and posted this helpful note over at his blog. Now, you too can directly benefit from Fitts’ Law.
Optimal Microwaving with Fitt’s μλ-Number

When pressing buttons on a microwave, “a lot” of time is wasted moving your finger around (as predicted by Fitt’s Law). You can regain these precious lost fractions of a second by modifying your button pressing behavior just slightly to minimize “costly” movements. The trick is to never press 0 (zero) on the microwave. Simply pick a number string of all the same number that is closest to your target time.

For instance if microwaving for 1 minute, which is normally 1-0-0, instead press 5-5 (55 seconds). You’ll be off a little bit but variations in microwave power make this negligible (when following directions on microwavable food for instance). Also, many microwaves allow input of seconds beyond 60sec (e.g. 00:88). So, in the above example 6-6 would work as well.

Click here for the whole post, complete with tables to aid your microwaving data entry speed.

Consumer Reports story on Automobile Ergonomics

Zoom over to the Consumer Reports car blog for a case study of accessibility by Gabe Shenhar .

Driving with an injury: Features that can ease the pain (excerpted):

…I have come to a new appreciation, surveying our vehicle test fleet, of what everyday life must be like for people with physical challenges or limited mobility.

For me right now, the key is low-effort everything and minimizing movements requiring my right arm. I have a newfound appreciation for a quiet cabin, a comfortable ride, easy access, and a view out that doesn’t require straining or craning. Automatic transmission is a given for now.

Here are 12 more items that make my temporary limitation easier to live with:

  1. Push-button start: Eliminates the need to twist the wrist to turn a key.
  2. Electronic parking brake: Requires only push/pull finger action, and also saves space.
  3. Adjustable armrest: Allows optimal positioning of the elbow.
  4. Power adjustable steering column: No need to grope beneath the steering column and pry loose a stiff lever.
  5. Power seat: Low-effort fore-and-aft and recline adjustments. Power lumbar support is a bonus.
  6. Automatic climate control: Set the temperature once and be done with it. No need to fumble for out-of-reach controls.
  7. Steering-wheel-mounted audio controls: Change volume and stations without having to lift a hand off the wheel.
  8. Rain-sensing wipers: No grasping or twisting a wiper lever.
  9. Auto headlights: No need to take my left hand off the wheel to turn them on or off.
  10. One-touch power windows (up and down): No need to press and hold, leaving my left hand on the wheel.
  11. Doors that unlock and open when you pull the inside latch: Takes away the need to look for the central lock switch.
  12. Strong door detents: Doors that stay open on my slightly sloped driveway without the need to fight them back.

911: Trying to fight slips via warnings

I got a newsletter in the mail today from the City of Raleigh. Here are some excerpts centering on the problems with our area code:


What do a child playing with a telephone, an unprotected non flip cell phone and someone dialing a ten-digit phone number in the 919 area code have in common? They all can lead to inadvertent calls to 911.

As much as 10 percent of the calls to 911 are accidental calls. If you do accidentally dial 911, stay on the line and speak to someone to let them know there is no emergency. Otherwise 911 center staff will need to call back or send a police officer to investigate to determine if there is an emergency.

Ten-digit dialing coupled with living in the 919 area code means more people now dial numbers with the area code and ours is a prime candidate for a mis-dial and accidentally calling 911.

Ways to minimize the risk are to use caution when dialing numbers using the area code.

They provided good information, but I believe it’s likely that fighting the 919 area code is an un-winnable battle. So, when you accidentally dial it, don’t hang up!

If you need a moment of humor, watch this humorous video about changing the emergency number.