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IBM/Compatible software for Automatic Design and Analysis of Taguchi Experiments 
(Review and Save Qualitek-4 Software Flyer)

Qualitek-4 Version 15.5+ with experiment planning guide and more.   Read Qualitek-4 Q&A.   Download Full-Featured Working DEMO and freely use it to design your own experiments using an L-8 array (No registration required) Our working  DEMO allows you to utilize L-8 array for designing your own experiments. It also let you explore many example experiments that use arrays of all sizes.

Software for Taguchi Design of Experiments
"Qualitek-4 from Nutek, Inc. automatically designs experiments based on user-indicated factors and levels. The program selects the array and assigns the factors to the appropriate column. For more complex experiments, there is a manual design option. The program also performs the three basic steps in analysis: main effect, analysis-of-variance, and optimum studies. Analysis can be performed using standard or signal-to-noise ratios of results for smaller, bigger, nominal, or dynamic characteristics. Results can be displayed using pie charts, bar graphs, or trial-data-range graphs. " - Quality Progress, ASQ.    
How to Purchase    Independent review    Read user Evaluations 

    Links to Related Sites & options
  1. Order Qualitek-4 software from Nutek
  2. Review How to Get Started with Qualitek-4
  3. Find out how people are applying DOE technique and Qualitek-4 Software
  4. Examine Sample Qualitek-4 Screens
  5. Our Dealers and resellers
  6. Follow Recommended Experiment Planning Steps
  7. Free Experiment Design Tips
  8. Review Overall Evaluation Criterion (OEC) theories and formulations
  9. Read Independent Qualitek-4 review
  10. Download Complimentary DOE_Taguchi_Basic_Manual (121 pages, FREE)

(a) Learn how to apply Qualitek-4 (Application Guide, WD, pdf)   (b) Review Qualitek-4 Capabilities (User Guide, PPT, pdf) (New)   (c) Review  Qualitek-4_Flyer  

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Sample Screens



Qualitek-4 (Windows 7)

Feel free to download the Full Featured Working Model (DEMO) of our Qualitek-4 program and use it for limited time to design and analyze your own experiments which utilize L-8 array. The DEMO program also contains over 50 example experiment files for your review. These example experiments include all exercises in the texts: A PRIMER ON THE TAGUCHI METHOD and DESIGN OF EXPERIMENTS USING THE TAGUCHI APPROACH, all problems and exercises in the our 4-day seminar handout, and many other practical case studies.  

Click here to view Qualitek-4 sample screens.
Learn about Qualitek-4 Capabilities (Review pdf - slides)

After you register, you will receive a auto-response email that will contain URL for the download site.

QUALITEK-4 is built to meet high standards of performance and precision. If for some reason you are not completely satisfied, you may return your software within two weeks of purchase for a full refund.

Book that helps you learn the use of the software: Design of Experiments Using the Taguchi Approach : 16 Steps to Product and Process Improvement  by Ranjit K. Roy Click here to visit our book site and purchase this book at a discount.

Make older programs run in Windows 7 (32 Bits)

If a program written for an earlier version of Windows doesn't run correctly, you can try changing the compatibility settings for the program, either manually or by using the Program Compatibility troubleshooter.

  1. Open the Program Compatibility troubleshooter by clicking the Start button Picture of the Start button, and then clicking Control Panel. In the search box, type troubleshooter, and then click Troubleshooting. Under Programs, click Run programs made for previous versions of Windows.

  2. Follow the instructions in the troubleshooter.

If you cannot install a program, insert the installation disc for the program and, using the troubleshooter, browse to the program's setup file, usually called Setup.exe, Install.exe, or something similar. The troubleshooter is not designed to work on programs that have an .msi file name extension.


(I) Windows 7, Systems: Problem - "The file ?C:\Windows\system32\MSVBVM60.dll? could not be opened"

Here is how I got it to work:
1.  Insert CD
2.  Right-click ?D:\Setup.exe?, select properties
3.  Select ?Compatibility? tab
4.  Check box ?Run this program in compatibility mode for:? and select ?Windows XP (Service Pack 3).  Click OK.
5.  Right-click ?D:\Setup.exe?, select ?Run As Administrator?.  Follow prompts answering yes/next, and completing the necessary information. 

 - submitted by Wong, Bruce, Qualcomm, San Francisco, CA.


European Users: Please be aware that you may need to change the regional settings to conform to American style decimal notation. [Likely error message: Error code 9 subscript out of range]. Qalitek-4 data file format requires English (United States) format. Set "English (United States)" as your preference.

(II) Problem due to REGIONAL SETTINGS: Qualitek-4 data file format requires English (United States) format. If your Windows is set to run in a non-English speaking settings, you may have difficulty with proper retrieval and display of results. If you experience such problems with the default experiment file PISTON.Q4W, you need to correct the setting following the steps shown:

a. From Windows (Xp) START, select  CONTROL PANEL. 
b. Select Regional and Language Options.
c. Select
Regional Options tab 
d. Set "English (United States)" as your preference.
e. Restart your computer and run Qualitek-4

REPORTING PROBLEMS: Should you experience problem installing and/or running Qualitek-4, please write us with information about YOUR SYSTEM, Reg# you used, SCREEN SHOT of problem or question you have.

WHAT DOES THE PROGRAM DO?                   
Qualitek-4 Capabilities: Design Experiments, Analyze Results, Calculate Loss/Savings, and many more.

Detail Capability Description: L-4, L-8, ...L-54, L-64, and L-81 orthogonal arrays ..2, 3 and 4 level Control and Noise factors ..On-line experiment planning and design help ..Spreadsheet data input and full screen editing ..User defined arrays for special experiment design... Automatic individual trial condition descriptions .. Preparation of results by combining multiple Criteria of Evaluations into a single index (OEC) ... Result import from text and spread sheet program files .. Writing report files to disk for word processing..  On-line Taguchi method overview ... Up to 120 repetitions (samples/trial) of results...Standard, S/N and Dynamic Characteristic analysis ... Fully automatic standard and S/N ratio analysis for bigger, smaller or nominal is better quality characteristic. ... Color graphic display and printing of... Main Effects ... Interactions ... Bar and Pie Chart of Factor Influences ... Stacked Bar Chart of Optimum Performance... Selective and automatic pooling. ..Confidence Interval computation ...Estimate of performance at Optimum Condition...Automatic S/N ratio to original units transformation

QT4 performs analysis automatically. When you select the type of analysis and the quality characteristic, the program computes Main Effects, performs ANOVA and determines the Optimum Condition with minimal user involvement. At each step, it allows you to select additional options from the screen menu or proceed directly to the next step.

Special Analysis Capabilities:
Automatic test of presence of interaction, Plot of interaction between two, three and four level factors, Least Squares quadratic curve fitting between average effects for three and four level factors, plot of Main Effects, Bar graph and Pie diagram for ANOVA results, Stacked diagram for factor contributions to Optimum, etc. Design and analysis of Dynamic Systems can be carried out for up to 12 different Signal and 10 different Noise levels.

Nutek offers free telephone support to all registered users with regard to installation and use of the software. In addition, Nutek provides on-site seminars with hands-on computer workshops and consulting services to help you apply the technique in your projects.

" ........ I like to acknowledge the utility of Qualitek-4 software. I used it during my postdoctoral study at Johns Hopkins University (2008-2010). We got good results from this and publish them in two research papers. Currently, I am serving as an assistant professor of mechanical engineering at University of the District of Columbia, at Washington DC. I am trying to incorporate Taguchi Design of Experiment and analysis training in undergraduate curriculum in Mechanical Engineering program. I believe students must be exposed to this useful technique to enable them solve critical engineering problems, or at least give them confidence to deal with multivariable optimization problems. While teaching I am also learning the depth of this useful technique. So thanks for putting this useful program together and making it available.

Price List:
Single copy - $ 1,996 ( Shipping charges are additional)

Contact us for prices on Multiple User License, Site and Corporate Site Licenses.


Download & learn Taguchi DOE (121 pages, FREE)   Purchase Textbooks



Placing Order: (Email us at for price quotation or purchase options)
Qualitek-4 REGULAR Version (CD-ROM and License letter. The Reference Manual is provided in PDF format on the CD-ROM)

Use your Company Purchase Order to place an order with us. (Issue PURCHASE ORDER in favor of RKRoy Associates. 3829 Quarton Road, Bloomfield Hills, MI 48302, USA), Send Bank Draft, Request INVOICE and/or pay using credit cards.
                           Your cost: $1,996 + $20 (shipping) = $2,016 USD (USA and Canada)
                           Your cost: $1,996 + $45 (shipping) = $2,041 USD (Outside USA)  

We strongly recommend that you download Qualitek-4 DEMO, install and try it before placing the order.  

Notes to Instructors
If you are an instructor teaching DOE/Taguchi Approach, you would be glad to discovered that the working DEMO version of Qualitek-4 software (which you downloaded) can be used to design over 15 different types of experiments that utilize the L-8 orthogonal array. If your class exercises are all based on L-8 array, you can freely distribute and your student can use it DEMO software for limited time. Here are all the different ways an L-8 array can be used.

(1) Four 2-Level factors (2) Five 2-Level factors   (3)  Six 2-Level factors (4) Seven 2-Level factors  (5)  Four 2-Level factors + Three interactions  (6)  Five 2-Level factors + Two interactions  (7)  Six 2-Level factors + One interaction  (8)  Four 2-Level factors + One 4-Level factor  (9)  Three 2-Level factors + One 4-Level factor  (10)  Two 2-Level factors + One 4-Level factor  (11)  One 2-Level factors + One 4-Level factor  (12)  Four 2-Level factors + One 3-Level factor  (13)  Three 2-Level factors + One 3-Level factor  (14)  Two 2-Level factors + One 3-Level factor  (15)  One 2-Level factors + One 3-Level factor

Example files in the QT4 disk also include over 50 experiments. You can examine these example experiments by using OPEN option from the Configuration Screen and select files with prefixes as: SEM-EX01.QT4, SEM-EX02.QT4, SEM-PP01, TEXT-E91.QT4, TEXT-E92, etc."

Capability Summary and Practice Steps

Summary Capabilities

Experiment Designs - You will have option to let Q4W design the experiment or do it yourself. In automatic design, you simply indicate what are your factors and levels, it selects the array and assigns the factors to the appropriate columns. You also have a limited selection of interactions and outer array designs. While automatic design can handle most of your common experiment designs, the manual design option allows you to create the special designs to suit your needs.

Running Experiments - Once you are satisfied with your experiment design, Q4W readily describes the recipes for you to carry out the experiments. It also suggest the random order of conducting each of the experiment which are described in separate pages to resemble an work order.

Analysis of Results - The three basic steps in analysis; Main Effect, ANOVA, and Optimum studies are carried out in sequence with click of OK buttons. Analyses can be performed using Standard or S/N for Smaller, Bigger, Nominal or Dynamic Characteristics.

Miscellaneous Features - Automatic test of presence of interaction, Plot of interaction between two, three and four level factors, Least Squares quadratic curve fitting between average effects for three and four level factors, plot of Main Effects, Bar graph and Pie diagram for ANOVA results, Stacked diagram for factor contributions to Optimum, etc.

Problems With Download: Send an email with above information.

Have a question with your applications?
Visit our DOE Expert Users site and ask any application related question you may have.

Have a question about experiment designs?
Be sure to visit our Tips on How to Design and Analyze Experiments and get a confirmation on your own experiment designs.

Learn about Qualitek-4 Capabilities (Review pdf - slides)

Getting Started with Qualitek-4

Experiment Planning
You must plan your experiment with utmost care.
Follow Recommended Experiment Planning Steps to conduct your planning session. You would benefit by closely following these steps regardless of the size of your team or experiment.

Experiment Designs
Prepare a list of factors and levels for a practice experiment (say 5 factors at 2-level each). Click on the
DESIGN menu and select Manual Design. Check L-8 for your design. When in design screen, describe factors and their levels by assigning to any rows (which are columns of the array). Since you will be using five of the seven available columns, click on the UNUSED button to designate the two columns as unused. Click OK to move to the orthogonal array screen. Click OK to experiment file screen. Supply only the first eight characters of your file name. The file extension, .Q4W, is automatically added.

After design is completed, you may review the trial condition by clicking on REVIEW menu and selecting Trial Condition. Should you want to carry out these experiments, you may print some or all the trial conditions.

Result Entry Once the experiments are carried out, you will need to enter the results by clicking on RESULT menu and then, selecting Enter Result option. If your result includes multiple evaluation criteria, you will select Multiple Criteria (OEC) option. Enter results/evaluation criteria as applicable. When done entering results, perform analysis following steps 3 - 8 as described above.

[Note that it is possible to unlock the full capabilities of the DEMO software by reinstalling with your own registration number. To secure your registration/license number for immediate use, write us with your purchase order.

 Practice Session

  1. Run Qualitek-4 (QT4) program from your computer and click OK past the Registration Screen to the experiment configuration screen.

  2. Notice that experiment file PISTON.Q4W is already loaded in memory. If not, OPEN file PISTON.Q4W. Since this experiment is already designed and carried out, it has results, and you are in a position to proceed with analysis of results. (In case of a new experiment, like the one you may want to try, you will always start with the design option.)

Proceed to Review and Analyze Results of PISTON and other example experiments. There are over 50 example experiments of all sizes included with the program.

  1. Click Analysis menu and select Standard Analysis. Since PISTON has three samples/results per trial, QT4 will remind you to perform S/N. Click OK to proceed. In the next screen check Bigger is Better Quality Characteristic and click OK.

4. Review results and click on Graph if you wish to view it. Click OK when done.

  1. While in the Main Effect screen, click Plot to view plots of Main Effect. Once you are in the graphics screen, click the "<<" or ">>" button at the bottom of the graph to display other factor plots. Click OK to return to Main Effect screen.

  2. Click on Interaction button, to display interaction plots between any two factors. Select the Automatic option if you want QT4 to calculate interaction between all possible factors, even though you may not have thought about all the interactions or included them in your study. QT4 calculates Nx(N-1)/2 possible pairs of interactions

for N factors and ranks them by Severity of their presence (Severity Index, 0 - 100%). Review the list to note the important pairs of interaction for future reference. Click OK or Cancel to return to Main Effect screen and click OK to proceed to ANOVA screen.

  1. In ANOVA screen, try POOLING the factor with least amount of influence (last column). To POOL, double click on the factor description. At prompt, review % Confidence Level and click OK. Notice how the ANOVA table gets updated. You can also try one or more of the following tasks.

  • a) Pool another factor with the least influence
    b) Reset ANOVA
    c) Pool all factors with less than 98.6% confidence level.
    d) Plot
    bar graph, pie chart, and Reset ANOVA
    e) Review Pie diagram

Click OK or Optimum button to move to the optimum screen

8. At the Optimum screen:

  1. Read expected response

  2. Convert this result to a real number when S/N analysis is used.

  3. Plot graph of factor contribution

  4. Find response for all factors at level 2

  5. Go back to ANOVA and pool all factors below 10% influence

  6. Determine 90% confidence interval of the optimum response

  7. Go to optimum screen

Click OK to return to the main screen. From the file menu select Open and select any other experiment file from the list of over 100 files. Analyze results by following steps 3 -8.

Q & A: About Qualitek-4 Capabilities +

 Qualitek-4 (QT4)

 Q&A on Qualitek-4 General Capabilities:  

 Q.    How many FACTORS can Qualitek-4 handle?  A.    Up to 63 factors (variables).

 Q.    What factor LEVELS can I use for my experiments using Qualitek-4?  A.   Qualitek-4 can handle 2-level, 3-level, and 4-level factors.

 Q.   Can Qualitek-4 help me PLAN my experiment?  A.  Experiment planning (Brainstorming) is an important step in the application. This step require strict a discipline to follow a logical sequence of discussions. Qualitek-4 “Plan” option provide the steps to follow and describe the thought process in details.

 Q How can one DESIGN experiments with Qualitek-4?  A.  Qualitek-4 allows you to design your experiments two ways. In MANUAL design, you will select the Orthogonal Array from a long list of standard arrays. In AUTOMATIC design option, once you describe your factors, QT4 will select the array and assign the factors to the column.

 Q.   Is it possible to design experiment with NOISE FACTORS?   A.  You can design experiments with noise factors using the OUTER ARRAY. In addition you also have the option to set up experiments with DYNAMIC CHARACTERISTICS.

 Q.   What type of ANALYSIS would I be able to perform?  A.  QT4 allows you to perform STANDARD (using averages and standard deviations) and Signal-to-Noise ratio (S/N) analyses (six different formulae). In either approach, you will have the option to select BIGGER, SMALLER, or NOMINAL Quality Characteristic.

 Q.   Can I study INTERACTION using QT4?  A.  Yes. QT4 has superior capabilities for interaction studies. Interaction between any two possible factor combinations (of levels 2, 3, or 4) can be graphically displayed and their SEVERITY OF PRESENCE compared. You can study all possible interactions among two factors regardless of whether you reserved any columns to study them or not.

 Q.   Can I graph and print MAIN EFFECTS?   A.  Yes. Single and multiple graphs displays are available.

 Q.   Can QT4 test for SIGNIFICANCE after ANOVA calculation?  A.  QT4 allows testing for significance each factor/interaction at a time or AUTOMATICALLY, all factors at a time.

 Q.   Is it possible to determine the relative influence of the factors from ANOVA in QT4?  A.  Yes. There are standard paretoized graphs (BAR and PIE graphs) are available.

 Q.   Could I get meaningful INTERPRETATION of results when performing S/N analysis?  A.  When S/N analysis is performed, QT4 provides a built-in option to TRANSFORM the expected performance data in terms of the units of the measured value.

 Q.   Would QT4 compute the CONFIDENCE INTERVAL (C.I.)?  A. Once the analysis is completed, QT4 allows you the option to compute C.I. at the desire confidence level. You will be able use these boundary values to validate the predicted performance at optimum by performing CONFIRMATION EXPERIMENTS.

 Q.   Can QT4 estimate the SAVINGS based on the performance improvements?  A.  Upon completion of analysis, QT4 can automatically calculate and show graphs of VARIATION REDUCTION AND expected cost SAVINGS (see sample screens  

Q&A on the technique: 

Q. What is the Taguchi method?  A. Taguchi method is a special (standardized) form of a statistical technique known as Design of Experiment (DOE). Users may refer to this subject as DOE/Taguchi. The technique is primarily used by engineers and quality assurance professionals for (1) product/process design optimization, and (2) production problem solving. 

Q. What does Qualitek-4 do for users? A.  Qualitek-4 helps users accomplish EXPERIMENT DESIGNS and ANALYSES of results. When applying Taguchi technique, Qualitek-4 can save time and money.

Q.  What kinds of activities use the DOE/Taguchi technique?  A.  Product and process design activities of all kinds of manufacturing industries can benefit from DOE/Taguchi technique. Most current users today are from automotive, electronics, plastics, food, medicine, pharmaceutical, aeronautical, and defense industries.

Q.  How does one learn about the technique?  A.  From seminars, self-study, application experience, co-workers. 



Q.  Are there books available on the subject?  A.  A number of texts are available on the subject. To see a complete list of reference, visit Nutek web site ( ). Also, in the Internet, search for sites under key words: TAGUCHI, SEMINAR, TEXTBOOK, SOFTWARE, CASE SUDY, etc.

Q.  Who is the author of Qualitek-4?  A.  Dr. Ranjit Roy of Nutek, Inc. is the designer and author of Qualitek-4. The software follows the same design and analysis format taught by him in his seminars and as described in his textbooks.

Q.  Is qualitek-4 easy to follow even if I have not read any books by the author or taken Nutek’s seminar?   A.  Qualitek-4’s capabilities and ANALYSIS steps follow a common sense (natural) approach. Perhaps this is why over 90% of its satisfied users are not those who have been through Nutek seminar on DOE/Taguchi.  

Q.  Is TRAINING on the technique and the software available?  A.  Dr. Ranjit Roy of Nutek, Inc. provides seminar/workshop on the application of the technique ( This 4-day session is intended to prepare the attendees for immediate application. The attendees to this workshop also learn how use Qualitek-4 for experiment DESIGN and ANALYSIS tasks.

Q.  Can I use the software for CLASSICAL DESIGN OF EXPERIMENT?  A.  Qualitek-4 is intended for experiments that utilize Taguchi ORTHOGONAL ARRAY. While it allows users to create their own array or modify standard Orthogonal Array, it does not check for the validity of such deviations.

Q.  Does the software help users learn the technique?  A.  No. Although, there is a large amount of information on the technique provided in the HELP section of Qualitek-4, and available free literature, it is not intended to teach users the technique. However, educated users who are familiar with the principles will find QT4’s automatic design capabilities a dependable option.  

Q.  Other than attending the seminar, is it possible to call for HELP on the technique?  A.  Support on the application of the technique is not included in the price of the software. You may however, contact Dr. Roy ( ) and discuss your particular situation. and ask questions. You may also consider joining the DOE Discussion group and ask questions for other users to help you (!forum/TDA-DG ). For general experiment design tips, visit .


Q&A on Program Installation and License:

Q.   Can I install QT4 multiple times?  A.  The registration number assigned to the user (displayed in the registration screen) clearly indicates single or multiple users. In case of change of system or relocation, you can use the program CD-RM to re-install the program to your new system.

Q.   What does the DEMO do for me?  A.  QT4 demo is a FULL FEATURED WORKING MODEL. It allows you to DESIGN and ANALYZE your own experiments that use an L-8 array. In addition, the demo contains over 50 example experiments of all sizes, which you can examine and print. (Qualitek-4 DEMO is as useful to you as a new vehicle which you are allowed to drive unlimited miles as long as you stay within the city limit.)

Q.   Is it possible to DUPLICATE QT4 program disks for backup?  A.  Yes. You may distribute the software CD-ROM freely, not the personal registration number. Without the registration number, the software will always be installed as a DEMO.

About Qualitek-4 (QT4)

The Taguchi method of experimental design is a popular statistical technique utilized by the manufacturing industry today. Qualite-4 is designed to automatically design and analyze results of Taguchi experiments.  Using its enhanced design capabilities, experienced users can layout experiments in a matter of minutes.  When results are entered and the type of analysis indicated, QT4 readily computes main effect, performs ANOVA, determines optimum condition, and prints presentation quality reports.  

Experiment Design - To help you design your experiments, QT4 allows you to do it yourself or in automatic design option, lets you simply indicate what are your factors and levels, and then it selects the array and assigns the factors to the appropriate columns. While automatic design can handle most of your common experiment designs, the manual design option allows you to create the special designs to suit your needs. Once you are satisfied with your experiment design, QT4 readily describes the recipes for you to carry out the experiments. It also suggests the random order of conducting each of the experiments, which are described in separate pages to resemble a work order.

Analysis - The three basic steps in analysis; Main Effect, ANOVA, and Optimum studies are carried out in sequence with click of OK buttons. Analyses can be performed using Standard or S/N for Smaller, Bigger, Nominal or Dynamic Characteristics.

Miscellaneous Features - Automatic test of presence of interaction, Plot of interaction between two, three and four level factors, Least Squares quadratic curve fitting between average effects for three and four level factors, plot of Main Effects, Bar graph and Pie diagram for ANOVA results, Stacked diagram for factor contributions to Optimum, etc. 

System Requirements: IBM/Compatibles,Windows  95 and later. 30 MB disk space.

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