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What If IBM Used the Fishbone and 5 Whys to Fix Their Crashing Tape Drives? - GoLeanSixSigma.com

In the early 1980s there was a countrywide failure of computer tape drives. The tape drives were all made by IBM, they were crashing in large and small businesses alike and no one knew why.

This was a big problem for business and definitely a big problem for IBM. We’ll take a stab at this problem with the advantage of “20-20 Hindsight” by reconstructing the historic mystery using two classic Lean Six Sigma Tools: The Fishbone Diagram & The 5 Whys technique.

The Fishbone Diagram

The Fishbone Diagram is one of the Seven Basic Tools of Quality (a shortlist of basic process improvement methods) popularized by the quality guru Kaoru Ishikawa. It’s also known as the Ishikawa Diagram and some inspired folks have dubbed it the “Fishikawa” to honor both the shape and the man famous for this user-friendly quality tool.

What Does a Fishbone Diagram Look Like?

Fishbone Diagram Bones - GoLeanSixSigma.com

How the Fishbone Works

The Fishbone is a structured brainstorming tool focused on exploring potential root causes of an issue. The “bones” of the fish are labeled for general categories of analysis such as:

  • “Policies”
  • “Procedures”
  • “Environment”

The idea is to ask what, within each category, could be causing the specific problem. As an example, “What about the environment could be causing the tape drives to crash?” And there could be many answers to that question:

  • The heat
  • The humidity
  • The air flow
  • The proximity of other equipment
  • Etc.

The idea is to switch from category to category while brainstorming potential root causes with a diverse group of people.

For the best range of ideas, it’s important to gather people together who have different views and roles within the process. In the case of IBM it would have been good to gather folks from:

  • Engineering
  • The Lab
  • Production
  • Shipping
  • Larger Customers

…to understand what was happening to the tape drives.

The idea is to switch from category to category while brainstorming potential root causes with a diverse group of people.

Using the Fishbone Diagram to Understand the Crashing Tape Drives

Fishbone Diagram - Crashing Tapes - GoLeanSixSigma.com

Working the Fishbone Diagram

Taking the category of “Materials” – one question would be, “Were the tape heads made of inferior raw materials?” Another category that you’ll find on most Fishbone diagrams is “People.”

Even though Dr. Deming said that 80% of problems are process related, there’s still 20% that might be due to the work force.

Even though Dr. Deming said that 80% of problems are process related, there’s still 20% that might be due to the work force. Were people mishandling the drives? They could look at the “Process” – did they have an inferior cleaning procedure? Many of the brainstormed root causes might have been worth exploring if the problem had been happening at a single location with one group of people in one environment. But this problem was happening across the country, which meant that the root cause had to be common to all of their customers.

At some point it became clear that something was wrong with the tape heads. But if there had been no changes in the manufacturing processes, no new suppliers and they used the same quality of raw materials, why would there be something wrong with the tape heads? Most of these tape drives were brand-new.

Time for another classic quality tool!

The 5 Whys

Combining the 5 Whys with The Fishbone Diagram constitutes the “Peanut Butter and Jelly Sandwich” of Root Cause Analysis.

Peanut Butter & Jelly

The 5 Whys is deceptively simple and bears a striking resemblance to the average conversation with a 5-year-old child. And that’s almost all you need to know to use this tool. It’s also known as the “Why-Because” tool for the same reason. The goal is to push past presenting symptoms and dig to root cause. It might take 5 Whys, 10 Whys or it might take just 1 Why.

Using 5 Whys on the Bad Tape Heads

5 Whys - Tape Heads - GoLeanSixSigma.com

The Root of the Problem

It turns out that Legionnaire’s Disease had always been present but the specific temperature and level of humidity being maintained by modern HVAC systems created a perfect breeding ground for the disease. The tape drives were often positioned near ventilation ducts so once they added the bactericide to the system to combat Legionnaire’s, the tape heads became coated with the tin contained in the solution. And the tin on the heads made them crash.

Solving for Root Cause

When a team of IBM chemists confirmed the root cause, the company considered the aspects they had control over. Eliminating the spread of Legionnaire’s completely was ideal, but no workplace would subject their people to uncomfortable environments. This left the option of revisiting the ingredients of the bactericide. It turned out to be easy to reformulate the solution without tin. Problem solved. They could have spent lots of time and money on the symptom by endlessly replacing expensive tape heads, but the Fishbone and the 5 Whys present the way to a permanent fix.

solution graphic -IBM tape drives

Challenges to using the Fishbone and the 5 Whys

“There’s No Time” and other Myths

Classic root cause analysis begins with the goal of moving past symptoms and solving a problem at its root, once and for all. But we often respond to problems by instituting immediate, temporary fixes. If my boss says, “Don’t bring me problems, bring me solutions” I might be tempted to put a patch in place because I’m so busy. I’m working hard just to keep up so I assume I have no time to get to the root. But, as the saying goes, “We don’t have time to fix it, but we have time to do it twice.”

“Fishing” Alone

Another mistake made in the interest of saving time is completing a Fishbone Diagram with a team of one – you. A key to the effectiveness of the Fishbone Diagram is the wisdom of the group. One person has only one view of the process whereas inviting the observations of others expands the problem-solving potential. The goal is to include diverse and even conflicting perspectives in order to increase the effectiveness of the brainstorming session. This also has the unintended consequence of increasing ownership of the inevitable changes that using this tool might lead to.

Selecting What to Pursue

Another hurdle, once the Fishbone is populated with ideas, is narrowing the list of causes down to a manageable number to investigate. If done right, the resulting diagram should be covered with “bones” or potential causes, but limited resources dictate that not every cause is a candidate for verification. Nor should they be. Multi-Voting, also known as N/3, is a simple tool that provides a quick visual prioritization.

To Multi-Vote:

  1. Add up the number of potential causes
  2. Divide the total by 3
  3. Give each member of the group the resulting number of votes

For example, if there are 21 potential root causes, 21/3 = 7. Everyone gets to put a mark next to the 7 causes they’d like investigated (sticky dots are good for this). The result is an instant shortlist to pursue.

Multi-Voting on the Fishbone Diagram

Multi-Voting Fishbone - GoLeanSixSigma.com

Pants on Fire

In the case of the crashing tape drives, the problem was so pervasive, public and costly that IBM had no choice but to immediately apply resources to solve the problem. But in our workaday lives we don’t always feel the urgency. That leaves us “fighting fires” all day just to keep things rolling. Consider this – if we’re choosing not to get to the root of process problems then we’re not just the firefighters, we’re also the arsonists!

If we’re choosing not to get to the root of process problems then we’re not just the firefighters, we’re also the arsonists!

Spending the time is always worth it, and these are quick and easy tools that require no advanced training. No more excuses – make a Fishbone & 5 Whys Sandwich and be a root cause hero!

Can you think of any ways you can use The Fishbone Diagram or The 5 Whys to solve a problem? Please share with us in the comments below!

Elisabeth Swan

Elisabeth is a Managing Partner & Executive Advisor at GoLeanSixSigma.com. For over 25 years, she's helped leading organizations like Amazon, Charles Schwab and Starwood Hotels & Resorts build problem-solving muscles with Lean Six Sigma to achieve their goals.
  • Tom Adamson

    Back then ‘herringbone diagrams’ as they were known, were a standard tool for IBM quality engineers. I wasn’t part of the ‘Quality Circle’ (a cross function group similar to a modern 6σ team) that solved this problem but they would have used the technique..
    🙂

  • Hey Tom – I have not heard about “Quality Circles” in some time – but I’m sure you’re right. And I’m sure it took a few more twists and turns than I’ve imagined. And as for the “Herringbone Diagram” reference – I just learned something new – Thank you!