QFD Tool

QFD Tool Documentation

How to build a House of Quality in QFD Tool, link it into a multi-stage QFD, and read the results. Button and field names below are exactly as they appear in the app, so you can follow along at app.qfdtool.com.

New to the method? Start with what QFD isand come back here when you are ready to build.

1. Getting started

Open app.qfdtool.com. You have three options:

  • Register — enter your email, follow the link in the confirmation letter, and a generated password will be emailed to you. You can change it later under Profile.
  • Try online — build a House of Quality right away without an account. Handy for a first look, but to keep your work you need to register.
  • Examples — browse ready-made documents to see what a finished QFD looks like. On the Pro plan, Clone this template copies an example into your documents so you can edit it.

2. Key concepts

Requirement (WHAT)
What the customer wants, in their words: “the kettle boils fast”. Listed on the left of the matrix.
Characteristic (HOW)
A measurable engineering parameter that delivers on it: “heating element power, W”. Listed along the top.
Relationship
How strongly a characteristic affects a requirement: 1 — weak, 3 — medium, 9 — strong.
Correlation (roof)
How characteristics affect each other. Raising power helps boiling time but may raise noise.
Stage
One House of Quality. A document can hold a chain of stages, each feeding the next.
Document
Your whole project: all stages, plus the list of competitors shared by every stage.

3. Create a document

  1. Go to Documents and click Create. A starter document called “My product” opens: one stage with a couple of placeholder requirements and characteristics, and three companies to compare. Rename or delete the placeholders as you go.
  2. To rename the document, click the gear button at the top right — the Edit document dialog opens.
  3. There is no Save button: changes are saved automatically. The header shows Saving... and then Saved.

Each stage sits in its own card. The buttons in the card’s top right corner download the stage as SVG, open the stage settings (gear) and delete the stage (trash can; the first stage cannot be deleted).

4. Customer requirements

Click the round + button below the list of requirements. In the Create requirement dialog fill in:

  • Requirement name — keep the customer’s wording: “easy to clean”, not “smooth inner coating”. The coating belongs in the characteristics.
  • Customer importance — a slider from 1 to 10.
  • Requirement type — a group such as “Usability” or “Safety”. Pick an existing one or choose New type and enter its name.

Click a requirement to edit it. Right-click it for Sort and Delete. Click a group header to rename the group.

Requirements can only be added on the first stage. On every following stage they are filled in automatically — see Multi-stage QFD.

5. Engineering characteristics

Click the round + button to the right of the characteristics. The Create characteristic dialog has:

  • Characteristic name and Unit — e.g. “Boiling time 1 l” and “s”. If you can’t name a unit, it’s probably not a characteristic yet.
  • Improvement direction — Increase, Decrease or Target value. Boiling time: decrease. Power: increase. Water temperature for green tea: a target value.
  • Current value and Target value — appear depending on the stage setting Type of characteristic improvement search (see benchmarking).
  • Characteristic type — a group, just like for requirements.

Click a characteristic to edit it; right-click for Sort and Delete.

6. Relationship matrix

Click a cell where a requirement and a characteristic meet. Each click moves to the next value:

empty→▽ 1 — weak→○ 3 — medium→● 9 — strong→empty

A tip from practice: a matrix where every cell is filled tells you nothing. Mark a strong relationship only when changing the characteristic clearly changes how the customer feels about the requirement. A requirement with no strong relationship at all is a sign that a characteristic is missing.

7. Correlation roof

In new documents the roof is already on; it is controlled by Enable roof in the stage settings (gear button on the stage card). Click a roof cell above a pair of characteristics. Each click moves throughPositive → Strong positive → Strong negative →Negative → empty.

Mark how the values themselves move: more heater power means more noise, so the correlation is positive. Whether that is good or bad, the app works out from the improvement directions: you want power up and noise down, so this pair is a conflict.

The roof is not decoration: correlations change the priorities, and how much is set by theCorrelation multiplier. Pairs of important characteristics that work against each other become technical conflicts in the summary report.

8. Competitors and benchmarking

Click Competitors at the top of the document. Add companies with the + button, give each a name and a color; one row is marked Your company. A new document starts with “Our”, “Competitor A” and “Competitor B” — rename them to real products. The list is shared by all stages.

Customer view: requirement assessments

With Enable requirement assessments turned on in the stage settings (it is on in new documents), a scoring area appears to the right of the requirements; click it to open the Assessment editor and rate each company from 1 to 5 on each requirement. Where the best competitor scores higher than you, the requirement’s importance goes up:

I = Ibase × (1 + α × (B − O))

where B is the best competitor’s score, O is yours, and α is the Requirement assessment multiplier.

Technical view: characteristic comparison

The stage setting Type of characteristic improvement search has three options:

  • None — characteristic values don’t affect priorities.
  • Competitive comparison — in the characteristic dialog, enter the Current value for every company. Priority is adjusted relative to the best competitor.
  • Target value — enter your current value and the target. Priority is adjusted by how far you are from the target.

The strength of the effect is set by the Characteristic comparison multiplier.

9. Implementation difficulty and engineering assessment

Two more stage settings make priorities more realistic. Each adds a row under the matrix; click the row to fill it in.

  • Use implementation difficulty — rate each characteristic from 1 to 5 in theImplementation difficulty dialog. The harder it is to improve, the lower its priority (Implementation difficulty multiplier controls how much).
  • Use engineering assessment — your engineers rate how good each characteristic is today, from 1 to 5, for you and for competitors. If you are behind the best competitor, priority goes up (Engineering assessment multiplier).

Every setting has a ? button next to it with the exact formula.

10. Reading the priorities

Under the matrix are two rows: Total score and Priority, %. They are calculated in this order:

  1. Base priority — the sum of requirement importance × relationship strength (1, 3 or 9) down the column.
  2. Adjusted for correlations in the roof, if the roof is on.
  3. Adjusted for characteristic comparison — competitors or target value.
  4. Adjusted for implementation difficulty.
  5. Adjusted for the engineering assessment.
  6. Converted to percentages, so all characteristics of a stage add up to 100%.

Wondering why a characteristic came out on top? Click its value in the Priority, % row. A dialog shows every step of the calculation: which requirements contributed, the correlations, every multiplier and the final result.

11. Multi-stage QFD

Click Add stage at the top of the document. The new stage takes the characteristics of the previous one as its requirements — only those whose Priority, % is at or above theMinimum threshold for requirement transfer, and with their priorities as importance. The threshold is a fraction from 0.01 to 0.3; the default 0.1 means 10%.

Change anything on stage one and every following stage recalculates. If a stage showsNo characteristics to transfer. Edit the previous stage., nothing on the previous stage clears the threshold — add relationships there or lower the threshold.

The classic four-phase chain looks like this:

  1. Product planning: customer requirements → product characteristics.
  2. Part deployment: product characteristics → part and assembly characteristics.
  3. Process planning: part characteristics → process parameters.
  4. Production planning: process parameters → production controls.

You don’t have to use all four — two stages are often enough for a coursework project. More on this inMulti-Stage QFD.

12. Diagrams and summary report

Below the stages you’ll find four blocks that look at the document as a whole:

  • Relationship diagram — all stages side by side, with links from requirements to characteristics and on to the next stage.
  • Requirements impact graph — the traceability graph. It shows how each customer requirement contributes to the parameters of the last stage. Hover over a node to see its contribution in percent. Read more: Requirement Traceability.
  • Legend — what the symbols in the matrix and the roof mean, and the colors of each company.
  • Summary report — three lists:
    • Driving requirements — the top 5 customer requirements by share of the final result. Over 50% is marked High, over 30% Medium: the whole design leans on one need, so make sure you understood it right.
    • Output characteristics — the top 5 parameters of the last stage, the ones that deserve the most attention.
    • Conflicts — up to 5 of the sharpest technical conflicts with their impact score and severity. A conflict is sharper when both characteristics have high priorities and the negative correlation is strong.

13. Export

  • Download at the top of the document saves a PDF with every stage, both diagrams, the legend and the summary report.
  • The download button on a stage card saves that stage as SVG — scalable, good for slides and printing.
  • The download buttons on the Relationship diagram and Requirements impact graph save them as SVG.

On the Free plan, exported files carry a watermark; on Pro they don’t.

14. Plans and limits

The Free plan gives you 2 documents with up to 2 stages, 10 requirements and 10 characteristics per stage, and every analysis. Pro removes the limits and the watermark and lets you clone examples. If you hit a limit, the app will tell you. See pricing for details.