Stoplight Estimates

Traditional projects thrive on estimates and humans are terrible at estimating. No really, we’re bad at this. Bad enough that college papers have been written correlating our failures with evolution. Bad enough that we’ve developed several competing terms to describe different perspectives on this same phenomena. Hofstader’s Law, Parkinson’s Law, and the Planning Fallacy all deal with the idea that you basically have no idea how long it will take you to finish what you’re doing. This is somewhat better than people who generally have no idea what they’re doing. At least your only problem is with time.

Poor estimations are more costly at the beginning of a project. This happens because a task done early is usually done early because other tasks depend on it. If the earlier task is misestimated and therefore delayed, this delay will be transferred to every other task that follows. For organizations doing operations, it’s easy to visualize how a machine going down early along the assembly line can impact the rest of the assembly line.

To compensate for poor estimates we’ve come up with some clever techniques. Jeff Sutherland talks about playing poker and Delphi estimating in his book on Scrum. Those techniques are great at helping human beings overcome errors in project estimations, but they can also cost quite a bit of time. Since time costs money, there are some scenarios where the estimation process isn’t worth the amount of effort to create the estimation.

Accurate estimates can significantly increase output, but making them timely can be a real challenge. Organizations conducting projects can put the estimations in the planning phase of their project. Organizations with ongoing operations need to incorporate the estimation process into their daily routine. Many organizations rely on historical data to do this, but doing this based upon historical data without checking its accuracy is a sure scenario leading to implementing Parkinson’s Law.

Every once in a while you meet someone who really gets it. You know the type. They don’t just understand their job, they really get how their job plays into the larger scheme of things. The United States Military Entrance Processing Command (USMEPCOM) has the responsibility to screen each applicant for military service. It’s a large job scaled across 65 different Military Entrance Processing Stations throughout the country. The MEPS have a job that focuses on meeting ongoing operational requirements, while its commanded by individuals primarily trained in more project oriented settings.

Recently I had the opportunity to visit the MEPS in Salt Lake City. There I discovered how their local management team has come up with an elegant estimation system to improve the efficiency of the entire MEPS. Applying their estimation system only cost 90 seconds in the first phase of processing, but gave the managers control over the processing flow for the entire organization.

The MEPS has the responsibility to review the applicant’s aptitude, physical health, and legal background. A typical applicant will arrive at the MEPS on an afternoon and take (or verify) their Armed Services Vocational Aptitude Battery (ASVAB) test. Afterwards, they’ll spend the night in a local hotel to arrive early the next morning at the MEPS for a medical evaluation, job selection, and background check. The medical evaluation is first, and as the first step of the day, it controls the processing flow for the rest of the MEPS.

The first step in a series controls the flow for the rest of the organization because it is a bottleneck for processing. If every applicant were a raw material and was processed the same exact way then the amount of processing time would be fixed for each iteration.

People aren’t raw materials. They’re our most valuable asset. A delay in medical can impact all the other sections. Because applicants and their medical history are different the amount of processing time varies between applications. Sometimes it varies significantly. Knowing how long to anticipate for each applicant can make a significant difference in controlling the flow at the MEPS.

The staff in Salt Lake generated an effective estimation system. At first, I mistook their ingenious method for a prioritization system. Discovering the beauty of its simple elegance has gotten me so excited that I’ve wanted to pen this post!

Most MEPS’s medical section will review the records of scheduled applicants a day or so before their arrival. In Salt Lake the team conducting the review and the team doing the medical processing was large enough that not everyone would remember each applicant just from a review the day before. Instead, after their records were reviewed someone would subscribe a green, yellow, or red dot to the applicant’s name tag that they would wear for the day. Green tagged applicants had records that were thinner than red tagged applicants. First thing in the morning the green tagged applicants would be front-loaded in the line to get some applicants on to the next phase of processing and reduce the down time in succeeding sections. People waiting to do work is a waste of those people’s efforts. This system increased efficiency within the MEPS, not just within a particular section.

Using this tagging system the medical section could control the pace of processing for the rest of the day. Once a small queue had built up of green tagged applicants a few of the yellow and red tagged applicants integrated into the system would be ready for further processing.

If this tag system were a priority system it would not increase efficiency even though the number of applicants processed through the medical section for the first hour would increase. Local efficiencies do not translate to organizational efficiencies. Imagine red tagged applicants being seen last by the medical staff, taking longer, and getting to the other sections later. If the processing queue at the other sections was exhausted while red tagged applicants were still in medical there would be no efficiency gained for the organization. This is why it’s not a priority system, it’s an estimation system that’s used to control flow for the entire organization.

People are bad at estimating, but we’ve compensated for our biology by creating techniques that allow us to overcome our bias. In order to be adopted, these estimation techniques must be efficient and simple to use. Leveraging the three color system the employees see every day on their way to work marries audience expectations with intended purpose.

An estimation technique is nothing more than a method for communicating and using the stop-light estimation system at the SLC MEPS is an efficient system for controlling processing flow for the next generation of military applicants. A good system can’t kelp you know what you’re doing, but it can help you get a better idea of how long it will take. Take that biology!