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Practical guide · Root cause analysis and problem solving

8D problem solving and the 8D report: the eight disciplines, D0 to D8, with a worked example

Short answer

8D, short for eight disciplines, is a team method for solving a serious or repeating quality problem and proving it will not come back. It runs from D0 to D8, and its core is two linked fixes: one for the cause that made the defect, and one for the control that let it reach the customer.

8D is a problem-solving process that Ford developed and that is now used across manufacturing, especially for customer complaints. In Ford's description of the Global 8D there are eight disciplines, D1 to D8, plus one preparation step, D0. The team protects the customer first (D3), then verifies the root cause and the escape point (D4), proves and installs permanent actions (D5 and D6), and changes the systems so the problem cannot return (D7). The record of all of it is the 8D report. Use 8D for a customer complaint, a repeat problem or one that crosses departments. For a small problem with one clear cause, a 5 Whys is faster.

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What is 8D problem solving?

Siemens says on its 8D report page that Ford first promulgated the method. Ford's own description of its current version, the Global 8D, was filed with the US vehicle safety regulator NHTSA in January 2024. It names eight disciplines, D1 to D8, plus one preparation step, D0. This guide follows Ford's wording.

The name 8D is also used for the document. An 8D report records the work: team, problem in numbers, containment, causes and how each was proved, permanent actions and evidence they worked. A customer with a complaint often asks for one, with a deadline for each step.

Does this problem need a full 8D?

  1. Is it a customer complaint, a repeat problem or one that crosses departments?

    If no

    A 5 Whys or an A3 is enough. One owner and a short chain of causes do not need nine steps.

  2. Is the cause still unknown?

    If no

    Make the fix, check it worked and change the standard. A report adds nothing.

  3. Can you write the problem as a count: what, where, how many?

    If no

    Get the count first. D2 and D3 depend on it.

  4. Every answer right

    Open the 8D at D0: take emergency actions to protect the customer, then form the team.

Three questions in order. If it is not a customer complaint, a repeat problem or one that crosses departments, use a 5 Whys or an A3. If the cause is already known, fix it and update the standard. If it cannot be written as a count, get the count first. Otherwise open an 8D at D0.

D0 is a decision as well as a preparation step. Most problems leave this flow before they reach D1.

The eight disciplines, D0 to D8, and what goes on the report

The eight disciplines and the step before them

  1. 1

    D0 Prepare

  2. 2

    D1 Establish the team

  3. 3

    D2 Describe the problem

  4. 4

    D3 Contain it

  5. 5

    D4 Root cause and escape point

  6. 6

    D5 Choose and verify actions

  7. 7

    D6 Implement and validate

  8. 8

    D7 Prevent recurrence

  9. 9

    D8 Recognize the team

D3 protects the customer while D4 to D7 fix the cause. D4 has two answers, not one: why it was made and why it got out.
  1. 1

    D0 Prepare

    Decide if a full 8D is needed.

  2. 2

    D1 Establish the team

    Pick a small team, a leader and a champion.

  3. 3

    D2 Describe the problem

    Write the problem as a count, with what it is not.

  4. 4

    D3 Contain it

    Isolate every customer from the problem.

  5. 5

    D4 Root cause and escape point

    Find the cause and the escape point, and prove both.

  6. 6

    D5 Choose and verify actions

    Choose the permanent actions and prove them first.

  7. 7

    D6 Implement and validate

    Install the actions and watch the results.

  8. 8

    D7 Prevent recurrence

    Change procedures so it cannot return.

  9. 9

    D8 Recognize the team

    Share the lessons and thank the team.

Source step names differ a little; the table follows Ford.

What each discipline asks for and what goes on the 8D report
StepWhat it asks forOn the 8D report
D0 PrepareDecide whether a full 8D is needed. If so, take emergency actions to protect the customer.The symptom, the date and the emergency actions already taken.
D1 TeamA small group with process or product knowledge, time and authority, with a champion and a team leader.Names, roles and functions.
D2 DescribeThe problem in numbers: what, where, when, how big, and what it is not.A problem statement with a count, and an is / is not comparison.
D3 ContainActions that isolate every customer from the problem until it is solved, validated as effective.Suspect, checked and bad counts by place.
D4 Root cause and escape pointThe cause that best explains the problem, and the point where it should have been caught and was not. Both verified.Each cause, the proof, and the causes ruled out.
D5 Choose and verifyThe best permanent action for the root cause, the escape point looked at again, proof it works without side effects.Each action linked to a cause, with trial results.
D6 Implement and validateInstall the actions, improve the control at the escape point, confirm they work, watch the results.Dates, owners and the results after the change.
D7 Prevent recurrenceChange the policies, practices and procedures so this and similar problems cannot return.Updated procedures; other parts and lines checked.
D8 RecognizePresent lessons learned and recognize the team.Lessons learned and sign-off.

The occurrence cause and the escape point

D4 is where an 8D differs from most root cause work. Siemens describes two paths: why the problem occurred, and why it escaped to the customer. Ford defines the escape point as the place in the process closest to where the problem is generated where the effect of the root cause should have been detected and contained, but was not.

That gives three questions. Why was the defect made? Why did no control catch it? Why did the system allow both? Fixing only the first leaves the same hole for the next defect. Ford's D6 improves the control at the escape point, and D7 takes the third question, because its answer sits in procedures and plans, not in one machine.

Where the occurrence cause and the escape point sit on the line

Example numbers
  1. Station 1

    Boring on CNC 4

    Insert changed, offset not re-entered

    Occurrence cause
  2. Station 2

    Final inspection

    5 housings per lot, pin gauge

    Escape point
  3. Station 3

    Packing and shipping

    No further check

  4. Station 4

    Customer incoming inspection

    Finds 6 of 120

    Found here

The housing passes four stations in order: boring, final inspection, packing and shipping, then the customer's incoming inspection. The occurrence cause is at boring and the escape point is at final inspection.

The same defect has two fixes in two places. The cause is removed where the housing is made, and the control is improved at the escape point, the last place it should have been stopped before the customer.

Tools sit inside D4: a 5 Whys follows one chain, a fishbone diagram lays out candidates, and the root cause analysis guide helps you choose.

An 8D example: a customer complaint worked through D0 to D8

Illustrative example, not a real customer. A machine shop makes aluminium pump housings. The customer's incoming inspection pulls 120 housings from a shipment of 600 and finds 6 with the bore under its lower limit, so the bearing will not seat: 5 percent of the sample. The customer asks for an 8D.

D0 and D1: finished goods go on hold the same day. A quality engineer leads, with the machinist, the process engineer and the shipping lead, and the plant manager is champion. D2: all 6 bad housings were bored on CNC 4 in Thursday's second shift. CNC 2 and CNC 3 make the same housing and none of theirs was bad.

D3 is a sort of every suspect housing with a go/no-go bore gauge. The customer still holds 600 minus the 120 inspected, which is 480. With the housings in transit, in finished goods and in process, that is 480 + 400 + 350 + 150 = 1,380 to check.

The D3 sort, place by place

Example numbers

  • At the customer, not yet inspected

    22 bad of 480

  • In transit

    18 bad of 400

  • Finished goods

    15 bad of 350

  • Work in process

    6 bad of 150

Four places were sorted: At the customer, not yet inspected, 22 bad of 480; In transit, 18 bad of 400; Finished goods, 15 bad of 350; Work in process, 6 bad of 150. In total 61 bad of 1,380.

1,380 housings sorted, 61 bad. With the 6 the customer found among its 120, the run is 1,500 housings with 67 bad, 4.5 percent.

The bad count is 22 + 18 + 15 + 6 = 61. Add the 120 the customer inspected, 6 of them bad, and the run is 1,500 housings with 67 bad, which is 4.5 percent. Every suspect housing is accounted for.

Illustrative: the three causes and how each was verified

Example numbers

  • Occurrence

    What it was
    The boring insert on CNC 4 was changed at 15:10 and the offset was not re-entered, so the bore ran near its lower limit.
    How it was verified
    With the old offset, 9 of 200 trial housings were under the limit, 4.5 percent, the field rate. Offset corrected: 0 of 200.

  • Escape

    What it was
    Final inspection checked 5 housings per lot with a pin gauge. At a 4.5 percent defect rate, a sample of 5 finds no bad housing about 79 times in 100 lots.
    How it was verified
    Sampling plan worked through: (1 - 0.045) to the power of 5 is 0.79, so about one lot in five would be caught.

  • System

    What it was
    The tool change sheet had no step for the offset or a first-housing check, and no one had tested the control plan's sample size against the defect rate it had to catch.
    How it was verified
    Sheet and plan read against the work as done on all three machines.
Three causes, three proofs. The escape cause is worked out from the sampling plan: a sample of 5 misses a 4.5 percent defect rate about four times in five.

A bad lot of bar stock was ruled out, because the same stock ran on CNC 2 with no defect. It stays on the report to show it was considered. The test: put the cause back and the defect returns, remove it and it goes.

Illustrative: the permanent actions and the proof before rollout

Example numbers

  • After every insert change, gauge the first housing and enter the offset. Tool change sheet updated.

    Removes
    The occurrence cause
    Proof at D5
    200 trial housings after a deliberate insert change: 0 under the limit.

  • A 100 percent go/no-go bore gauge at pack-out replaces the sample of 5.

    Removes
    The escape point
    Proof at D5
    10 known-bad housings mixed into 500 good ones: the gauge found 10 of 10.
One action for each cause that was verified, and a number from a trial for each before anything goes into production.

D6: both actions went in on day 12. Containment stayed on until three full weeks of normal production had passed: 6,300 housings made, none under the limit, no new complaint. A trial shows an action can work; only weeks of production show it does. D7: the new step went onto CNC 2 and CNC 3, other housings on the same boring bar were checked, and the control plan now ties sample size to the defect it must catch. D8: the team is thanked and the report goes out.

8D vs A3 vs CAPA vs 5 Whys

The four sit at different levels. CAPA is the requirement to find the cause, remove it and prove it. 8D and A3 are ways to do that work, and 5 Whys is a tool inside them.

8D, A3, CAPA and 5 Whys compared
8DA3CAPA5 Whys
What it isA team process, D0 to D8One sheet, background to follow-upThe quality system's corrective and preventive action processA questioning technique
Use it forA complaint, a repeat problem or one that crosses departmentsA problem one team owns, inside the plantAny nonconformity needing a recorded actionA problem with a short chain of causes
What you end withAn 8D report, often sent to a customerThe A3 sheetA CAPA record and effectiveness checkA chain from the symptom to a cause
Contains containment and escape pointYes, D3 and D4Only if the team adds themCorrection and corrective action; no escape point stepNo

The A3 guide covers the one-page format, the CAPA guide maps the disciplines to CAPA steps, and problem solving methods compares them all.

Common 8D mistakes

Four common 8D mistakes and what to do instead

  • Mistake

    Containment mistaken for the fix

    What goes wrong: Sorting stops the complaints, the pressure drops and the cause is never found.

    Do this instead

    Treat D3 as temporary. Keep it on until D6 shows weeks of clean production.

  • Mistake

    The root cause stops at operator error

    What goes wrong: "The machinist forgot" ends the investigation and changes nothing.

    Do this instead

    Ask why the system let one slip reach the customer: the sheet, the check, the sample size.

  • Mistake

    No verification of the action

    What goes wrong: A plausible action goes in and is assumed to work.

    Do this instead

    Try it before rollout (D5) and measure after (D6). Keep the numbers on the report.

  • Mistake

    No prevention or horizontal deployment

    What goes wrong: The same gap on the next machine, part or site fails the same way.

    Do this instead

    At D7, list the similar parts, lines and sites and check each one.

Each fix is the same move: do not let a step end on a belief. Count it, test it or write it down.

The 8D report your customer asks for

Customers set the form and the deadlines, and some use their own version of the steps. Read their supplier requirements and use their form if they give one. The facts to carry are the same, because a reviewer can only check what is written down.

  • The problem statement has a count, and an is / is not comparison.
  • The containment counts reconcile: every suspect part is accounted for.
  • Both the occurrence cause and the escape point are there, each with its proof.
  • Every action points to a cause, and the proof is a number.
  • D7 names the other parts, lines or sites checked.

The free 8D report template is built around these checks, and the 8D poster puts the nine steps on a wall.

8D templates and software

Start D2 with the 5W1H template or an is / is not sheet, run D4 with the 5 Whys template, and track actions on the CAPA log. The non-conformance report guide covers the step before an 8D.

In LeanSuite, Non-Conformance (NCR) has structured workflows that guide teams through every step of an 8D, from containment to prevention. AI Root Cause Analysis starts from a described problem and returns likely root causes with an action plan, and Lean Studio has 30 ready-made boards including the 8D.

Non-Conformance Management

Run an 8D in LeanSuite

Guide teams through every step of an 8D, from containment to prevention.

See Non-Conformance ManagementBest CAPA software

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All our articles on this subject are in the root cause analysis and problem solving topic.

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FAQ

Questions about 8D problem solving

  1. 8D, or eight disciplines, is a team method for solving a serious or repeating quality problem and proving it will not come back. It runs from D0, a preparation step, through D1 to D8: form the team, describe the problem, contain it, find the root cause and the escape point, choose and verify permanent actions, implement and validate them, prevent recurrence and recognize the team.

  2. 8D is not one of the Six Sigma phases. It is a team method for a complaint or a repeat problem, and Siemens says Ford first promulgated it. Plants that use Six Sigma often run both: 8D when a customer needs containment and a report, DMAIC when a chronic problem has an unknown cause and needs data.

  3. In Ford's description the disciplines are D1 establish the team, D2 describe the problem, D3 develop interim containment actions, D4 define and verify the root cause and escape point, D5 define and verify permanent corrective actions, D6 implement and validate them, D7 prevent recurrence and D8 recognize the team. D0 comes first: evaluate whether a full 8D is needed and take emergency response actions to protect the customer.

  4. It is the place in the process, closest to where the problem is generated, where the effect of the root cause should have been detected and contained but was not. D4 verifies the escape point as well as the cause, and D6 improves the control there, so the next defect is stopped before it reaches the customer.

  5. In an 8D the measurements are counts. D2 states the problem with a count, D3 records suspect, checked and bad parts by location, and D5 and D6 give the results of the trial and of the weeks after the change. There is no single 8D unit; each number is there so a reviewer can check the claim.

  6. The report records each step: the team, a problem statement with a count, the containment with suspect, checked and bad counts, the occurrence cause and the escape point with the proof of each, the permanent actions with trial and validation results, and what was done to prevent recurrence. The worked example on this page follows a bore defect on a machined housing from the complaint to the closed report.

  7. 8D is a team process of nine steps with containment and the escape point built in, and it ends in a report that is often sent to a customer. An A3 puts a problem on one sheet from background to follow-up and suits a problem a team owns inside the plant. Use 8D for a complaint or repeat problem, and an A3 when one owner can tell the whole story on a page.

  8. CAPA is the quality system requirement to find the cause of a problem, correct it and prove the action worked. 8D is one way of doing that work, with fixed steps and a report. An 8D is often how a CAPA is carried out for a customer complaint, and the CAPA record holds the evidence.

  9. Yes. The free 8D report template on this site is an Excel tracker, a PDF and an editable Word form covering D0 to D8, with due dates, containment counts, occurrence and escape causes, and a worked example. A free 8D problem solving poster is also available.

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