CLT10 common mistakes
CLT10 · Understand the traps and how to avoid them.
Treating the seven wastes as a memorized list and labeling an activity by its surface appearance (for example calling any waiting 'waiting waste') instead of tracing whether the step creates value for the customer or is required by the current process.
Candidates study the waste names as vocabulary and never practice the value/no-value decision on concrete process steps, so they pick the label that sounds closest rather than the one that survives a value test.
What to do instead
For every waste question, run the three-question test explicitly: does the customer pay for this step, does it change the product or information in a way the customer needs, and is it done right the first time. Classify only after answering all three, and distinguish necessary non-value-added work (such as regulatory inspection or setup) from pure waste.
Reading a value stream map as a snapshot of lead time only, ignoring the distinction between process time, wait time, and the ratio of value-added time to total lead time, and then proposing kaizen on the wrong step.
Candidates equate 'current state map' with 'find the biggest number' and skip the timeline at the bottom of the map, which is where most of the lead time usually sits.
What to do instead
On every VSM question, compute total lead time by summing inventory divided by daily demand across queues, compute total process time by summing cycle times, and state the value-added ratio. Direct improvement effort to the largest queue or the constraint, not to the longest cycle time by default.
Confusing push with pull by judging only whether a schedule exists, rather than whether downstream consumption authorizes upstream production, and misidentifying a supermarket or FIFO lane as a push system.
Candidates memorize 'pull equals kanban' without understanding that the defining feature is the trigger for replenishment, so any signal card looks like pull and any schedule looks like push.
What to do instead
Ask what authorizes the next unit of production. If the answer is a downstream withdrawal, a kanban, or a consumed FIFO slot, it is pull. If the answer is a forecast-driven schedule released to each process independently, it is push. Then check whether the pull signal is bounded by a WIP cap.
Defining takt time as cycle time, or computing takt from working hours without subtracting breaks, planned downtime, and demand variability, then judging line balance against the wrong denominator.
The two terms are used loosely in everyday speech, and candidates skip the available-time calculation because it looks like arithmetic rather than lean reasoning.
What to do instead
Write takt time as available operating time divided by customer demand per period, and state the available time you used. Compare each operator's cycle time to takt, not to the average, and identify the bottleneck operator whose cycle time exceeds takt.
Treating jidoka as synonymous with andon cords or stopping the line, and missing that the concept requires detection, stopping, and fixing the root cause so the abnormality cannot recur.
Candidates associate jidoka with the most visible artifact (the cord or the light) and overlook the separation of human work from machine work and the built-in detection of abnormalities.
What to do instead
Describe jidoka as three linked elements: detect the abnormality at the source, stop immediately so bad units are not passed on, and countermeasure the cause. For any scenario, ask whether the answer stops the process, contains the defect, and prevents recurrence; if it only alerts, it is incomplete.
Answering 5S questions by reciting the five words in order and proposing a cleanup campaign, rather than recognizing that sustain and standardize are the parts that make the first three stick.
The acronym is easy to memorize, and candidates treat 5S as housekeeping rather than as a foundation for standard work and visual control.
What to do instead
For 5S scenarios, identify which S is actually failing. If the workplace relapses after cleaning, the failure is in standardize or sustain, and the fix is a documented standard, a visual audit, and a named owner, not another cleanup day.
Writing or evaluating an A3 as a status report or a proposal document, with a solution on the left side and no evidence of the current condition, instead of following the left-to-right thinking sequence from background to countermeasure to follow-up.
Candidates are used to business documents that lead with the recommendation, and they have not internalized that the A3 is a thinking process whose value is in the reasoning, not the format.
What to do instead
Check the A3 for the sequence: background tied to a strategic need, current condition with data, target condition with a measurable gap, root cause analysis, countermeasures matched to causes, and a follow-up plan with owner and date. If the countermeasure appears before the current condition is quantified, the A3 fails.
Confusing hoshin kanri with ordinary annual planning or with a list of projects, and failing to trace how a top-level objective breaks down into measurable targets and daily actions with catchball dialogue.
Candidates see the word 'planning' and map it to budget cycles, missing the alignment mechanism and the review cadence that distinguish hoshin from a project portfolio.
What to do instead
Look for the chain: a small number of breakthrough objectives, each broken into annual targets, then into departmental and team actions, with explicit two-way negotiation (catchball) and periodic review. If the scenario has many unrelated goals with no linkage or review, it is not hoshin.
Attributing a failed lean transformation to tool choice or to resistant employees, rather than to leadership behavior, management system, and daily habits, and proposing training as the remedy.
Tool-based answers feel concrete and safe, and candidates underestimate how much of lean success depends on leaders going to the gemba, asking questions, and changing their own routines.
What to do instead
For culture and change questions, separate technical change from management-system change. Ask whether leaders model the behavior, whether the daily management routine (tiered meetings, gemba walks, leader standard work) exists, and whether people are developed through problem solving. Prescribe leader behavior and system changes before training volume.
Choosing a metric because it is easy to measure, such as utilization or units produced per hour, and defending it even when it drives overproduction and longer lead time.
Local efficiency metrics match conventional accounting intuition, and candidates have not practiced predicting the side effects of a metric on flow.
What to do instead
For any metric question, trace the behavior it rewards. If maximizing it creates inventory, batches, or defects passed downstream, it is the wrong metric for a flow system. Prefer measures tied to the customer: lead time, on-time delivery, first pass yield, and WIP level.