ISSS Round Robin Activities 2010

 Final Comment on the results of the 1st round of the ISSS RR 2010

The ISSS RR 2010 has been completed.  All participants received the detailed results (see documents "Round Robin 2010 Results").

Download ofi Statement.

Unfortunately, only 10 out of 20 ISSS Scientific Body members have participated in the ISSS RR 2010. This low number is disappointing since ISSS membership includes the unwritten obligation to participate in such activities which are also extremely valuable to meet the requirements of ISO 17025 accreditation. Thus, it should be mandatory not to miss the next round.

The aim of the RR is twofold:

1. to verify the lab's compliance with the majority of the participating labs. By eliminating the labs with outlier results from the general evaluation (s*) the z-scores are reliable and the check is relevant. Z-scores below 2 can be seen as good performance, z-scores below 1 as very good performance.
2. to determine the accuracy of the various test procedures. This is expressed by the parameters Repeatability "r" and Reproducibility "R".

ofi has performed the evaluation of these parameters and presents this in the attached document ("RR 2010: Accuracy Parameters"). Some of the r and R values look rather odd (i.e. large). However, it should be taken into account that the parameters assume a probability of 95% !! This means that the regular standard deviation values are multiplied with the factor 2.8.

It can be seen that the r&R values are dependant on the type of surface tested.

• Ball Rebound Hockeyball
• these data need  further review in respect to the individually used reference rebound heights on concrete  used by the different labs . Thus, no further comment at this time (comment to follow).
  
• Ball Rebound Football
• r-Values on synthetic surfaces with low resilience are in the range of 2.4%, on low resilient artificial turf 3.3%, but is 11% on soft artificial turf. The relationship R/r is between 1.1 and 3.5
  
• Ball Rebound Basketball
• is rather similar as Football
  
• Vertical Deformation
• the r- and R- values of surface SS2 are incorrectly influenced by the fact that the SS2a and SS2b sub-samples were non-compliant. The parameters should be determined with 1 sample of each lab because scattering of results within the same sample SS2a or SS2b are apparently much lower.
  It is obvious that the repeatability on soft artificial turf is much less satisfying.
  
• Force Reduction
• r- and R-values of SS2 must be ignored because of the irregular effect of the negative sample compliance. In general it seems to be clear that Force Reduction exhibits rather good repeatability and reproducibility.
  

Conclusion

The accuracies of the tests procedures derived from the results of the ISSS RR 2010 are suitable to withstand scrutiny. This information should be used by the CEN TC217 Committee to develop a Precision Statement for the various types of sports surfaces.

June 2010
ISSS RR Panel

ISSS Round Robin 2010 - State of Program

In December of last year, the ISSS announced it would undertake a Round Robin Evaluation of several test methods.  This first ISSS Round Robin 2010 has been successfully completed with approximately 20 international participants. The evaluation of the results was published on Monday, March 12, 2010 by the  ofi-PTS Organization.  The data is organized using lab codes which were randomly assigned by  ofi -PTS to the participating labs for confidentiality.  The evaluation documents show the whole range of results for each of the included tests (Force Reduction, Vertical Deformation and Ball Rebound).  In addition, the position of the labs relative to the overall average is characterized by the statistical parameter Z-Score.  This parameter, which is always shown as a positive value, employs the group average as 'zero' and measures the distance from this point for each result.  Thus, the comparison of a lab within the lab group can be seen from its average Z-Score. The ISSS RR Panel will discuss the results and prepare a proposal for a Precision Statement for the test procedures used.

For information on the scientific background of the RR you may study the  ofi -PTS document "Testing Scheme Report".

ISSS' Round Robin activitiy will be continued shortly with additional tests.

Thank you to all of the participating laboratories.

ISSS Round Robin Panel

Background 

The Round Robin project  approved  at the ISSS AGM 2009 in Cologne has commenced and the first round of inter-lab testing will take place  after the beginning of  the  year.  The time table allows for registrations through the end of January 2010, testing completed by the end of February with evaluations beginning in March.  This is planned to be an annual programme with different test procedures offered in different years. This is the first project investigating the proficiency and accuracy of the various test procedures - a knowledge which is  very much overdue  yet mandatory for reliable testing.  The result of the RR will also demonstrate whether improvements of the test specification are needed. Simultaneously, the individual labs can check whether they are in compliance with the general results of the Round Robin.

The ISSS has entered into an agreement with the ofi test house in Vienna (ofi = Österreichisches Forschungsinstitut / Austrian Research Institute). ofi is equipped with a  professional proficiency testing department  which has been dealing with this type of evaluations on an on-going basis for more than 10 years. You may see all its information at http://www.ofi-pts.com/. Dr. Thomas Karall will perform the methodological and statistical organization and evaluation of the RR (thomas.karall@ofi.at) while Susana Ruiz de Castroviejo from CST takes care of all communication issues on behalf of the ISSS. The   management of the entire  RR procedure  will be conducted  through the internet. ofi has already introduced a new section  entitled "Sports Surface Testing Procedures" covering the specific tests to be applied to sports surfaces.  The reporting method of an ofi Round Robin  result  was presented at the ISSS Technical Meeting in Rome in 2008 (Taber Abrasion Test): download document.

The ISSS Round Robin project was initiated by a study prepared by Graham Tipp Round Robin Proposal and discussed with the ISSS labs Round Robin Comments. The principles compiled herein are taken into account by the ofi Proficiency Testing concept.

This program is designed to produce genuine, impartial evidence of the precision and reliability of the various test procedures and a compliance control of the  participating labs. The  format of the RR  complies with  the rules of prISO 17043 "Conformity Assessment - General Requirements for Proficiency Testing". Participation in this  program will aid in meeting  the obligation required for ISO 17025 accreditation . Additional standards used are - ISO/IEC Guide 43-1 - ISO/DIS 13528 - DIN V 55394-1 and the determination of accuracy of the test methods according to - ISO 5725, page 1-6. All data are entered on-line to the ofi evaluation programme by the individual labs. The labs have access to their individual section (password protected). Entered data cannot be changed/altered by anyone. The data are processed by the ofi programme automatically in a standardized way. No names of participants are disclosed by ofi. All these features ensure objective, reliable and confidential results.

All professional test houses as well as labs of manufacturers are invited to participate. Cost for participation is € 255.00 per test procedure (registration, supply of samples and evaluation; payable directly to ofi-pts see attached "Guideline-pts 2010").  The design of this programme is most cost-effective since no traveling is incurred. Results of the RR will be scrutinized by the ISSS RR Panel and a discussion including all participants will follow.

For the beginning of theannual  RR activity, the following test procedures have been agreed to

• Force Reduction acc. EN 14808
• Vertical Deformation acc. EN 14809
• Ball Rebound acc. EN 12235 (Basketball, Football, Hockey ball)

OFI-PTS will provide surface samples (50x50cm) as follows

• Synthetic Surface hard + soft
• Artificial Turf with no infill: Hockey type + Football type

In ordertoexpedite this activity,interested labs may pre-register immediatelybut mustregisterno later thanJanuary31, 2010at www.ofi-pts.com. Surface samples will be providedwithin 2 weeks after registration (guaranteed). Deadline for delivery of resultsshould bebyFebruary 26.Thegeneral evaluation as well as the individual situation canbedownloaded from the OFI-PTS website right afterthe last participant hasentered his data.ofialso offers the option to order formal results forinclusion in yourISO or otherdocumentation.

A guidline document may be downloaded here.