First e-mail

Gomez-Taylor.Maria to: Harry B McCarty 10/04/2011 01:42 PM

4 attachments

----- Forwarded by Maria Gomez-Taylor/DC/USEPA/US on 10/04/2011 01:29 PM

-----

From: "Tyler Martin" <tyler.martin@ossmaine.com>

To: Maria Gomez-Taylor/DC/USEPA/US@EPA,

 <dean.smith@ossmaine.com>

Cc: <carl.tripp@ossmaine.com>, Denis Borum/DC/USEPA/US@EPA,

 Maryt Smith/DC/USEPA/US@EPA

Date: 10/15/2010 04:26 PM

Subject: RE: Request for Information

Maria,

I have tried to contact you with some questions, but we decided to start

sending what information we have ready at this time. This is not the

complete data to meet your request of item 1 below. Instead, this is a

start to address what you have asked for.

-'SLV_Lab_Sheets_Raw_Data' contains the single laboratory reports

directly

from the lab that performed the study, as no anonymity was requested or

granted for this study.

-'MLV_Lab_Sheets_Noteboooks' contain the multi-lab validation raw data,

as

requested in item 2 of your email. Names and identifying info are

redacted.

-'Expanded ASTM D7575 Validation Report - for EPA 10-15-2010' is an

expanded

version of the D7575 validation report that is in the docket for the

recent

method update rule. The replicates have been compiled for the MDL, IPR,

and

QC work in both single and multi lab studies in Appendix C, as

requested.

Appendix D has only a slight change describing sb in more detail. The

main

body text and tables did not change at all.

-'Comparability - SLV complete' contains a step-by-step walkthrough of

the

comparability statistics from the single lab validation

Again, we realize that the attachments do not satisfy all of your

requests.

However, we did not want to take any longer to start providing

information,

and we are also hoping to get some feedback from you. The Comparability

statistics are laid out in great detail, and we would like to know if

this

is sufficient info in a good format, and if this level of detail is
needed

for all other calculation steps, as it is quite time consuming. Please

let

us know your thoughts.

Answers to your other questions:

3. Grubbs test was applied to the difference between log-transformed

triplicate means of each method.

4. A single RMSD assessment was applied to all data from the single lab

validation simultaneously.

5. I found the current guidance on 1664 available online at

http://www.epa.gov/waterscience/methods/method/oil/1664guide.pdf a bit

easier to follow. Page 2-4 describes the MSE in detail. It is the mean

of

the variances of the log-transformed replicates calculated for each

sample/matrix/method.

6. The Comparability file shows in detail: for j=number of samples,

i=number of test methods, and k=number of replicates; df1=j,

df2=i*j*(k-1).

These exact values varied a bit as outliers were excluded.

7. The true values were determined by OSS personnel, who were the

experts in

the method D7575. As approved by the relevant ASTM committees and

agreed to

by Mr. Redding and Mr. Walker, EPA 1664 was not performed on these

samples.

We hope this is a good start, and look forward to hearing from you.

Regards,

-Tyler

Tyler Martin, Ph. D.

Senior Research Engineer

OSS - Orono Spectral Solutions

983 Stillwater Ave., Old Town, ME 04468

PHONE: 1-857-277-7843 (direct line)

PHONE: 1-866-269-8007 (toll free)

FAX: 1-866-660-4759

EMAIL: tyler.martin@ossmaine.com

WEB: www.ossmaine.com

-------------------------------------------------------

Please be advised that this email may contain confidential information.

If

you are not the intended recipient, please do not read, copy or

re-transmit

this email. If you have received this email in error, please notify us

by

email by replying to the sender and by telephone (call us at +1

866-269-8007) and delete this message and any attachments. Thank you in

advance for your cooperation and assistance.

-----Original Message-----

From: Gomez-Taylor.Maria@epamail.epa.gov

[mailto:Gomez-Taylor.Maria@epamail.epa.gov]
Sent: Friday, October 08, 2010 11:27 AM

To: dean.smith@ossmaine.com

Cc: carl.tripp@ossmaine.com; tyler.martin@ossmaine.com;

Borum.Denis@epamail.epa.gov; Smith.Maryt@epamail.epa.gov

Subject: Request for Information

Hello Mr. Smith,

We asked our contractor to start reviewing the single-laboratory and

multi-laboratory validation studies for ASTM Method D-7575-10. After

preliminary review of the reports, the contractor is requesting the

following information. I know that you are already assembling

information I requested earlier this week. The specific information

requested below would help expedite the contractor's review.

1. An Excel spreadsheet or spreadsheets containing data from the

single-and multi-laboratory studies with cell formulas for calculations

of the intermediate and final statistics presented in the report.

Examples of intermediate and final statistics being requested are:

a. Details on any data transformations and outlier removal,

b. Step-by-step calculations of the RMSD and RMSDmax,

c. Calculation of the variance components, including sb, used in the

calculation of the multi-lab acceptance criteria.

This information will allow the contractor to mathematically trace

conclusions and statements in the report to the data.

2. Copies of the completed reporting forms in Appendix A with the

laboratory name and other identifying information redacted.

Specific questions regarding single-laboratory validation:

3. In the description of the method comparability calculations in

Appendix D, it is stated that "outliers in deviation between the methods

are removed. Two Grubbs outliers were found: Day 1 of the seven day POTW

study failed at the 97.5% significance level and subsequently Day 5

failed at the 95% significance level." What specific values were the

outlier tests applied

to; i.e., were the tests applied to individual results, the replicate

means, the difference between the means of the log-transformed values,

the square of the difference between the means of the log-transformed

values, or a different set of values?

4. Was a single RMSD assessment performed using all data shown in

Tables C-1 to C-3 (other than those that were removed as outliers, or

removed due to being below the ML), or were the data in Table C-3

assessed separately?

5. How was the value of s2 (as given in the formulas for the RMSD

assessment shown in Appendix C of the 1995 Freon Replacement study

report) calculated; e.g., as the Mean Squared Error calculated by

fitting an ANOVA model, the mean of the variances of the replicates

calculated for each sample/matrix/method, or following some other

calculation?

6. What were the numerator and denominator degrees of freedom used for

the F-statistic in the RMSD assessment?

Specific question regarding the multi-laboratory validation report:
7. In Tables C7 and C8, how were the true values known?

_______________________

Please let me know if you have any questions.

Regards,

Maria Gomez-Taylor, Ph.D.

1200 Pennsylvania Avenue

N.W. Washington, D.C. 20460

Phone: 202-566-1005

E-mail: gomez-taylor.maria@epa.gov

(See attached file: MLV_Lab_Sheets_Notebooks.pdf)(See attached file:

Expanded ASTM D7575 Validation Report - for EPA 10-15-2010.docx)(See

attached file: SLV_Lab_Sheets_Raw_Data.pdf)(See attached file:

Comparability - SLV complete.xls)