Ideas for airlines on how to make lines and wait time shorter for passengers

As an avid airline passenger, I’ve flown on many different airlines (most major airlines) and visited many different US airports (and a few international airports). What I've noticed is that the process of how to get checked-in, through security, and loaded onto the plane seem to be ripe with opportunity.

Let’s break this down into three major processes:

• Checking in
• Going through security
• Loading the plane.

Checking In

This area has been steadily improving over the past few years, especially with online check-in and electronic ticketing. I actually don’t have many complaints with this process (unless the airline is not using these options). The best situation is when the check-in kiosks are separated from the line. I dislike when you have to wait in a line that has both people waiting for kiosks, and those with questions for the attendants. It gets confusing, and slows down the process for those only needing the kiosks. There are also people who aren't paying attention when a kiosk opens up, so you have to try to get their attention. I also prefer when the airline takes your checked bag after you weigh and tag, instead of giving it to you to give to security. I think that has gone away now, but it was a bunch of wasted steps.

Going through security

My observations and experience with going through the security line is that the line slows down due to the natural variation (common cause) in the time it takes passengers to get organized and loaded onto the conveyor belt. Each passenger is quite different on how long it takes to remove their clothing items (coats, belts, watches and shoes), take out their liquids, take laptops out of bags, take out coins and money, and get their baggage placed on the conveyor. Today, it's a high pressure race to get things off and out of bags with no room to maneuver, and no place to set things. It’s the most stressful part for me when I fly. People are constantly pushing to get their bags on the conveyor behind me. While under pressure, you will ultimately forget your belt or something in your pocket, and have to go back through (rework).

I'm guessing that the scanning process of the bags is most often times the bottleneck, so if we apply the theory of constraints to this issue, the baggage scanning should never be waiting for any bags, yet it is often times idle, due to this variation in passengers getting prepared for the scanner.

I would like to see a staging area after you get your ID and ticket checked, where you can take as long as you want to get all your stuff organized into the trays. I would like to see a big open area with table and chairs where you can sit down, open your bags and pull out the liquids, take off your shoes and laptop, and go at your own pace. Similar to the seating you have after the security line.  This would be helpful for all travelers, but especially elderly, those with children, or those with lots of carry-ons.

When you are done, then you get in line for the X-ray scanning (could be multiple lines to choose from), and it's much less stressful. The only downside is moving your bags and trays back to the conveyor, but hopefully it could be placed close enough to the conveyor where that would not be a huge issue.

By the way, the new pre-check TSA system (keep on your shoes and belt, your laptop in its case, and your 3-1-1 compliant bag in your carry-on.) is awesome, and I hope they roll that out as the standard process in the future!

Loading the plane

I like the idea of loading the window seats first, then the middle seats, then the aisle seats, starting from the back of the plane, and working forwards.

A variation of that was developed by Dr. Jason Steffen, where the rows and sides of the plane are alternated, to create more space between passengers to allow for maneuvering and room to store bags in the overhead.

You can see Steffen’s method in the video below.

When the airlines started charging more for checked bags, this made the loading time much longer. I don’t understand why they did this, other than it was less costly for them (although I’m not quite sure why).

One possible reason for this change is that it will force people to reduce their total amount of luggage. I’d be curious to see if this has happened, or if everyone has just tried to cram their luggage into a carry-on. This has definitely increased the time to load a plane, and now more people are forced to have their carry-on luggage checked at the gate instead, since there is no more room on the plane. This leads to delays while they roam the overhead units looking for space once they are already in the plane, then it leads to rework where passengers finally realize it is full, and have to get their bag back up to the front of the plane to get it checked. I think they should require us to check all our bags, so you only get a personal bag. Let the baggage handlers do their job (which they probably do pretty efficiently), and reduce the amount of time needed for loading the plane.

The only other option I can think for this rule change is that the airlines are saving money with the baggage handlers, therefore if less bags go through the checked bag process, then they will need less workers. This seems to be the most logical reason to me. Unfortunately, this kind of solution is typical of many companies we work with, who try to save money in one area, and it makes the problem worse in another area. The worst part is that they are pushing the problem to their customers, which is the last thing you want to do.  This has to impact the airline’s ability to turn around flights with the longer loading times, which could reduce how many flights occur per day ($$$).

If you're trying to save fuel by reducing baggage, I like Samoa Air’s approach of charging airline ticket cost based on the total weight of the passenger, which includes their own weight and the weight of their baggage. If weight is indeed a big driver of airline fuel spending, then this makes the most sense.

It might be controversial when people are individually being weighed, but I think it’s the most fair from a price perspective. Then it doesn’t matter how many different bags you bring, you are responsible for the total weight.

One other issue I have with loading the planes is when they call out the group numbers. I like the group number idea, but there are two issues:

1) I am never sure what group number was called (audio is poor quality, wasn't paying attention, etc). There is no visual indicator about the current group number. I'm not the only one either, since I always see people asking each other what group number was called. A simple group number on the display boards would make a big difference.

2) The bigger issue is that everyone clusters right near the ticket agent, so often times I think I'm in a line heading towards the front, when in fact the people ahead of me are not in my group, and are blocking the way. When I realize the line at the ticket agent has cleared and the people ahead of me aren't moving, it's too late to get through the cluster, and they quickly call the next group number. Now I'm in the middle of the next group.

United Airlines actually has a good visual control to solve both of these problems...

They have markers for each group number (including first class and preferred boarding), so you simply get in the line associated with your group number, and there is no confusion as to which group is being loaded currently. They are the only airline I have seen doing this.

Finally, a quick note about unloading the plane. It would be nice to require everyone to stay in their seats, to allow "pre-authorized" passengers with short layovers to get off the plane first. This was done during one flight I was on, and it seemed to work really well. There were probably some people who didn't have short layovers that got off in the early group, but I think it worked for most of the people trying to catch their next flight. I think they set the cut off for those with a layover of 30 minutes or less. This would reduce the number of missed flights and reschedules, plus increase customer satisfaction. The rest of the passengers seemed to be OK with this idea, since they probably wished someone had done that for them when they were in the same situation. They only had to wait a couple minutes, so it really wasn't much of a delay for everyone else. We'll see if this idea catches on...

Many of you are avid travelers. Do you agree with our ideas? What are your recommendations?

Update: Here is an article from Portland International on some of their efficiency improvements in different aspects of the airport >>>

Top 3 things to validate before removing test or inspection steps

A process with excellent capability usually means there is a very small probability that the natural variation of the process will exceed the specification limits. Without getting into a detailed discussion, let's assume you are calculating Ppk for this process. We will discuss Cpk and Ppk confusion at another time, but PQ Systems does a good job of explaining why we will be using Ppk for this discussion:

Estimated sigma and the related capability indices (Cp, Cpk, and Cr) are used to measure the potential capability of a system to meet customer needs. Use it when you want to analyze a system's aptitude to perform.

Actual or calculated sigma (sigma of the individuals) and the related indices (Pp, Ppk, and Pr) are used to measure the performance of a system to meet customer needs. Use it when you want to measure a system's actual process performance.

Most customers would like Ppk to be 1.33 or greater (4 sigma), where the probability of having a failure is less than 1% (99.38% success), even with a process shift of 1.5 standard deviations. If you improve the process even further, you might even achieve 6 sigma, which would be a success rate of 99.99966%. This also depends on your industry, as some lower volume industries might accept a lower Ppk, while higher volume production may require Ppk greater than 2.0.

For the purpose of this article, let's assume the process has been in place for some time (full rate production levels), not a discussion during design and development of a new process or product. In addition, even if your process has a 100% yield does not mean it has good capability. Therefore, a pass/fail step should switch from attribute to variable data collection if possible, so Ppk can eventually be calculated.

At some point, the chance of having a failure is so small, that the question comes up from management: "Why are we still testing or inspecting this characteristic, if it is unlikely to fail?"  

Can the test or inspection be eliminated completely? Can we reduce it from 100% down to 50% or 25% or 10%? From a lean perspective, inspection and test are non-value added but necessary (avoiding problems from getting to the customer or further into the process), but perhaps these steps are not even necessary because the process is so good.

In most cases, the end customer will have some say in this matter, especially if they provide the requirements to you. By default, they will be highly resistant to any test or inspection removals. It adds risk to their processes, and they usually don't see any benefit. 

Given this resistance, what evidence is required to alleviate their concerns, and allow approval of a reduction or elimination in a test or inspection step?

We have not found any formal documentation on how to deal with this situations. If someone has some guidance (any industry), please let us know so we can share with our clients. 

Here is our typical response when asked this question...

There are three areas to look at to prove test or inspection reduction to a customer: Stability, Capability and Risk Mitigation.

Stability: Consistent process data results (no outliers and no trends or shifts on the control chart) that have been happening over a "long" period of time (varies by industry). Ppk calculations assume a stable process, so stability provides confidence that the calculation of Ppk will be maintained in the future. This also implies a sufficient sample size has been obtained, that clearly shows the underlying distribution of the data (normal, weibull, lognormal, etc).

Capability: Good capability results (Ppk > 1.33 minimum, but preferably over 2.0, which equates to Six Sigma performance). Ppk calculation is also based upon an assumption of normality, so if that's not valid, the Ppk results may be incorrect.

Risk Mitigation: Clear documentation of how the process will not produce defects, shift, trend away from the average, or increase in variation in the future. Typically this involves evidence of mistake proofing, SPC knowledge, and operator training.

Even if there was some clearly defined process for making this decision, an agreement between customer and supplier will always be required. We recommend you have this discussion as early as possible before preparing a package, to make sure the customer will consider this option, and the amount of evidence is agreed upon ahead of time. There may be very high severity characteristics (safety critical or operation critical) that will be difficult to justify for sampling, even with high Ppk values, due to the severity of even one escape.

Example

Let's look at a generic example, and see how we compare against the three criteria. Let's assume you have an inspection process that measures the gap between two parts. The gap is recorded into a database, and the results are tracked on an Individuals and Moving Range chart (SPC control chart). 

Stable? 

As you can see, there is no out of control conditions identified on either chart, so we feel confident that the process has been stable during the time period of this chart. Let's assume this is a six month history of 100 data points.

Capable? 

Since we've already shown a stable process, we next check the normality of the data. The chart looks good, but technically it fails the normality test. However, this is due to the resolution of our data. If we go one more decimal point, the normality test passes. Therefore, our data is normally distributed.

Next, we look at the capability histogram compared to the customer requirements, and look at the Ppk calculation.

Clearly, the data falls well within the lower and upper specification (tolerance) limits of 15 +/- 0.20. 

Ppk is calculated at 2.40, which is better than a six sigma process. There would be a very remote chance of a failure due to random chance. Therefore, the process is considered capable.

Risk Mitigation?

Now that we have capable and stable performance, we still need to give the customer confidence that we can maintain this performance into the future. 

We recommend including the following information in your discussions and proposal:

• List of past defects and outliers, along with root cause corrective action that includes a mistake proofing device implemented to prevent recurrence.

• Operator and engineering records on SPC training classes completed.

• Documentation showing how the operator enters data, reviews charts for out of control conditions, and takes action when required.

• Updated PFMEA with a history of completed actions that reduced the highest RPN scores, and regular meeting minutes showing updates to the PFMEA with a cross-functional team.

• History of SPC charts on this process, to prove that the SPC charts are not brand new, and that the common and special cause variation has been improved over time.

• Operator training program, to show how new employees are properly trained and supervised with regular oversight until skill competency is proven.

• Good documentation and work instructions on the process (mainly pictures, clear explanations, cautions, color-coding, etc), to give confidence that a new operator would not produce defects.

• Key parameters that have been flowed to the supplier to help control variation on this measurement.

• History of a stable supply chain (no recent supplier changes or disruptions).

Not every single one of these will be required. Some customers might ask for more than this. However, the more you can complete and provide with your proposal, the higher the probability it will be approved. Want to improve your chances even more? Show the customer what cost savings you can provide to them by reducing or eliminating the step!

Most likely, the first request for elimination will be rejected by your customer, but hopefully they will agree to a reduced sampling plan (check every other part, instead of every one). After a few months of success, maybe every 4th or 10th part will be checked, until eventually the test or inspection is eliminated.

Conclusion

Without any clear industry documentation or guidance on how to reduce or eliminate inspection or test in your process, we hope this provides you with a starting point, to see if your process is eligible or not. The more evidence you can share with your customer regarding stability, capability and risk mitigation will increase the chance that they will agree to a reduction or elimination of a test or inspection step. Giving the customer a financial incentive to approve doesn't hurt either...

What are your experiences with this? Have you been successful? Does your customer refuse to accept any evidence?

How to calculate time savings after reducing distance traveled

One of the goals of a lean kaizen event is to reduce the overall lead time, from when an order is officially placed by your customers, until you deliver the order to the customer. The longer the lead time, the more money your company needs to have in cash flow and inventory to account for this delay.

Typically, the lead time is significantly longer than the actual time to produce the product or service, often times 10-20X longer than the cycle time (only 5-10% of the lead time is spent working on the order, the rest of the time it sits or gets moved around the facility). For example, if your process is 5 steps, and each step takes one hour to complete, it is not surprising that it can take 50 hours or longer to process an order through the system (5 hours of cycle time x 10 = 50 hours).

One of the first improvements you can make to your process is to reduce the time spent BETWEEN the process steps, in order to reduce the amount of delays and excess transportation in the process.

This can be measured by using a distance measuring wheel to follow the flow of products or people through the process, or measured by AutoCAD or tape measure. The total distance traveled can be calculated before and after the improvements to determine time savings.

According to the book Making Materials Flow, each step of walking is equivalent to 2.5 feet. Each step (2.5 ft) is equivalent to 0.6 secs. If you use the metric system, one step equates to 0.762 meters. Said another way, for every 4.166 feet traveled (1.27 meters), one second of time is wasted.

Therefore, if your process distance traveled is 10,000 feet per day, let's look at the calculations:

10,000 ft / 4.1667 ft/sec = 2400 seconds = 40 minutes = 0.67 hours

3048 m / 1.27 m/sec = 2400 seconds = 40 minutes = 0.67 hours

Next, you can multiply your labor rate x the number of hours of travel. For example, if the labor rate is $30 per hour (including all benefits), then $30 x 0.67 hours = $20 of wasted time per day. If you work 20 days per month, then the cost is $400 per month wasted due to travel.

Any other calculations you've used to capture walking distance savings?

Zero defects does not mean the problem is solved

One of the common mistakes made by companies is the assumption that the lack of defects means the problem has gone away.

Especially in low volume companies, when a particular problem does not reoccur in a small sample, it is easy to claim victory and move on to a new problem. However, without adequate sample size, that can be a mistake.

Determining adequate sample size depends on two factors: how confident you want to be, and how big the problem was prior to the improvement.

Let's assume a defect was occurring in a process approximately 20% of the time. The team comes up with a solution and implements it. 10 more units are produced from the process with the "new solution" and there are zero defects. Success! Actually, not so fast...

How likely were we to get zero defects, if nothing was improved? It turns out, the odds are pretty good. We can calculate that exactly using Minitab.

Go to Calc --> Probability Distributions --> Binomial (Pass/Fail data) 

Let's say the failure rate is 20%, so enter 0.2 for Event Probability and 10 for # of trials, with a input constant = zero (number of failures) 

Binomial with n = 10 and p = 0.2 
x  P( X <= x )0     0.107374 

This output means that there is only a 10-11% chance of seeing zero failures in 10 samples, if we still have a failure rate of 20%. We ideally would like to see less than 5% chance.

If the failure rate is higher at 50%, then the chance of seeing zero failures would be much lower (since it's pretty likely to have a failure show up under normal conditions).

Binomial with n = 10 and p = 0.5 
x  P( X <= x ) 
0    0.0009766 

If the failure rate is only 10%, then the chance of seeing zero failures would be higher (since it's less likely to have a failure under normal conditions) 

Binomial with n = 10 and p = 0.1 
x  P( X <= x ) 
0     0.348678 

34% is too high of a risk to conclude that the problem went away. If you get a probability less than 5% (such as with a failure rate of 50%), then you can conclude that the problem likely has gone away. If greater than 5% (such as with failure rate of 10% or 20%), then we don't have enough samples to "claim victory". We would need to collect more samples. You can keep adding trials to Minitab until it gives you a sample size that shows a probability less than 5% (less than 0.05). 

In this example, with 10 samples and zero failures observed, the original failure rate should have been at least 25% before the problem was fixed, in order to statistically say that the problem has been resolved. If your previous failure rate was less than that (say 15%), then you will need more samples (trials) before you can feel confident the problem has been resolved.

Minitab has another method for figuring out the correct sample size and confidence. We will cover that in a later discussion (or email us if you need help).

Don't have Minitab? The calculations are easy manually for zero defects...

• Probability of zero defects with 10% failure rate = (0.9 * 0.9 * 0.9 * 0.9 * 0.9 * 0.9 * 0.9 * 0.9 * 0.9 * 0.9) = 0.3486

• Probability of zero defects with 20% failure rate = (0.8 * 0.8 * 0.8 * 0.8 * 0.8 * 0.8 * 0.8 * 0.8 * 0.8 * 0.8) = 0.1073

Next time you are reviewing your data, make sure you have the statistical confidence to say that the problem has gone away, so you don't get embarrassed later when it returns.

What do all the lines and boxes mean on a boxplot?

The Boxplot is one of simplest graphical tools to look at, and a tool I use very frequently when first reviewing my data sets. It is a great visual tool for showing the variation and average of a data set, that is not sensitive to outliers (nonparametric approach). The chart shows how the data breaks down by categories, to help you identify areas of concern or potential causes of your problem.

However, it is the most confusing chart to explain how each piece of the box is calculated. When teaching a basic statistics class, I actually avoid discussing the boxplot, because it brings about many questions and becomes a distraction for the class attendees.

When we look at the boxplot simplistically, it gives us a quick understanding of our data. Let's look at an example from Minitab.

You should be able to draw some simple conclusions from the chart

• The boxplot for the paint data shows that paint blend 4 has both the highest median and least variability, with an interquartile range of only 3.10.
• Blends 1 and 3 appear to have roughly similar medians and variability.
• Blend 2 has the lowest median and greatest variability, with an interquartile range of 11.72. The short whiskers indicate clumps of data near the box endpoints.
• There are no outliers in the data

Ultimately, the very next question is always "how are the box and lines calculated?"

Let's breakdown the chart to help clarify it.

1. Determine Median (50th percentile) = 146
2. Determine 1st quartile (25th percentile) = 141.5
3. Determine 3rd quartile (75th percentile) = 150
4. Calculate outlier range “whiskers” as (1.5 * (Q3-Q1)) = 12.75 from median (133.25 to 158.75)
5. Calculate Interquartile Range (IQR) by taking Q3 – Q1 = 150 – 141.5 = 8.5
6. Draw line through median
7. Add asterisks if data outside outlier range

You can also download the Boxplot guide below for future reference.

Hopefully this helps you understand box plots, and you see the need to use them prior to analyzing
any data set.

8 ways why batching is bad for your business

One of the most common questions we get when reviewing a process:

"What's wrong with batching? I can produce so many more widgets when I do it this way?"

When I first started out in Lean, I had the same questions. It seems more efficient to the worker, and therefore it doesn't make sense to them that someone would want to change that. It took a few improvements before things started to sink in for me.

Just so everyone is on the same page, when you batch, you don't complete tasks one item at a time, you wait until you have a few items, then complete the task all at once. Usually this is because the time to get setup to complete the task takes a while, so it's more efficient to do the task all at once. However, the time waiting for a large enough batch to complete causes the next step to wait, then it generates a large amount of inventory all at once, which is unable to deal with the inventory and therefore it will need to be stored or will sit waiting to be worked on.

Don't believe us? Check out this video of envelope stuffing, and you'll understand why one at a time is better.


Here are a list of reasons why batching and inventory is bad:

1) Delays in detecting problems - The parts are not allowed to move to the next process until the whole batch is complete, so any problems found later in the process are delayed, adding to the number of items with problems that will need to be reworked or thrown away, increasing costs.
2) Taking up resources - Any items being produced that are not needed right now are taking up time at that process step, that could be better spent on things that are needed, which delays deliveries to customers.
3) Inventory cost - The labor and cost to process the items has been spent, but since it's not needed yet, it will take longer to get paid by the customer, which reduces cash flow and the cost of capital (money that could be getting a return on investment).
4) Cost to store inventory - Inventory needs to be stored, so there is a cost to process and record it, package it to protect it from damage, put it somewhere out of the way (requiring more floor space, which adds to the cost of utilities for lighting, heating and cooling).
5) Potential for problems - Once the inventory is stored, there is an increased chance that it gets damaged, deteriorates, corrodes, etc. This requires it to be redone or reworked or discarded, which costs money.
6) Loss of customers - If a customer cancels the order, or asks for a different version, or the part is no longer made available for sale, then the inventory becomes worthless, so the expense of buying and purchasing the items is lost.
7) Cost to dispose - There may be additional costs to deal with the scrap or unneeded items beyond the wasted labor and material costs, such as landfill disposal costs, cost to transport or pickup the items, fill out paperwork, or even properly recycle it.
8) Perception differs from reality - As seen in the video, the perception of batching may not actually result in faster processing.

Don't get me wrong, there are situations where batching is a better option in the short term (large setup times, low cost of inventory, inconsistent deliveries, etc). There are other situations, especially when ordering from a supplier, where travel and bulk discounts come into play. For these situations, an economic order quantity can be calculated that considers all these extra costs, to decide how large the batch size could be. However, in general the goal is to minimize the size of batches as much as possible by making the setup times less.

What examples do you have that helped you understand inventory and one piece flow? What other problems does inventory and batching create?

8 steps for passing the ASQ Six Sigma Green Belt or Black Belt exam

We have taught many students how to prepare for ASQ exams. I've even taken (and passed) the Certified Quality Engineer (CQE) exam once, and the ASQ Black Belt exam twice (do not let your certification expire, or you will need to re-take the exam!).

We often get asked what the best approach for passing the exam should be.

I'm going to assume that you have some prior Six Sigma or statistics training, and you are looking for a way to refresh yourself on the topics.

Since many people are now taking the Certified Six Sigma Green Belt (CSSGB) exam, I will focus a little more on that exam, but many of the tips apply to the Black Belt (CSSBB) exam.

If you have not taken any Six Sigma training, I would recommend checking out our webpage on getting free online Green Belt training

1) Order the Certified Six Sigma Green Belt Primer (QCI) and Solution Text - This will provide you with almost everything you need to know to pass the test. If you know the material in this book, there is a really good chance you will pass. You don't have to sign up for the exam yet, we will discuss that later on...


2) Read every word of each chapter once. I would start at the beginning and work your way through the book in order. This will get you familiar with every topic and definition. 

Are you limited by time, or want to be more strategic in your efforts? Since they provide you with the percentage of questions by section (according to the 2nd Edition of the CSSGB primer), start from the top of this list, and work your way down, focusing on the sections you don't know as well.

3) After taking the sample questions, mark your book with a post-it note or post-it flag/arrow for keywords and topics that you want to retrieve quickly during the exam. There is an index in the back of the book, but some people find the post-its more helpful. The sections do not always seem intuitive based on their name, so don't think that will be much help during the exam.

4) Answer all sample test questions at the end of each chapter. The questions are based on old test questions, That means:

• They are a good representation of the type of wording and questions you will get on the actual exam.
• They may have been thrown out or poorly worded, so you will get frustrated with some of the answers.

Therefore, don't get too wrapped up in one or two questions. You will notice that reading the question clearly is very important. Don't just skim it and think you understand what they are asking for.

After taking the sample questions, check your answers in the primer, and review the questions you got incorrect. Read the explanation, and see if it makes sense. Go back into the primer and make notes about the question. Often times, there is a similar example in the training material that you can add comments in the margin.

NOTE: You will not be able to bring the practice questions or solution text into the exam. It is open book, so almost everything else you can bring in for reference, except those two things.

If you still aren't sure why the answer was correct, seek out some help from people in your company or network who can help you out. We will be setting up some exam review sessions starting in October 2013, so contact us for dates of online and in-person review sessions.

5) After reading the book, and taking the sample questions, you should feel comfortable knowing if you have a chance at passing. If you feel like you understand most of the content, and are getting most of the questions correct (at least 50% correct on the first time through), then you are probably ready to sign up for the exam. There is no official cut-off or % correct, since it is based on a difficulty rating, but the rule of thumb is around 70% correct. Study and prepare so you will get at least 80% correct, so you don't push your luck.

6) After signing up for the exam, continue working on the problems you struggled with. Some additional training might be helpful, if the primer book is not explaining it very well. Again, check out the free online Green Belt training from BMGi. If you can't find any helpful training on the topic, contact us and we'll point you in the right direction.

7) Read the blog we wrote titled "15 last minute tips before taking an ASQ Green or Black Belt exam" at least one month prior to the exam date. Some of these tips are pretty simple, but it helps to think about everything, and be proactive.

8) Any additional free time should be spent re-reading and reviewing each section, with an emphasis on the sections with the most questions (see Pareto chart above). If you don't know what a Pareto chart is, you should start planning to re-take the exam!

If you feel more comfortable having some reference materials with you (not required), I would recommend borrowing some of the following books from a colleague (or purchase if necessary):

• The Certified Six Sigma Green Belt Handbook

• The Six Sigma Handbook

• Implementing Six Sigma

There is a lot here to remember. Luckily, we have recently developed an "ASQ Six Sigma Exam Reminder System", that will email you as the exam date nears, with these tips and tricks to help you pass the exam.

Good luck! 

Let us know if you have other tips or tricks that worked for you!