# Presentation: 247284

## Laboratory Evaluation Help Center

- Step-by-Step Guidance for “**Types of Data Needed****”**

## NOTICE

- The forms provided on the BQS website for project information and data collection are not live at this time. The programming should be completed soon, and we will notify you when you can enter data directly into the web.
- For now, please copy the form to your computer and use them as templates.

## Initial Data vs. On-going Data

- Before you select a lab, you review data representative of your analytes, matrices, concentrations and data quality.

**INTIAL**

**ON-GOING**

- After a lab is selected, you continue to collect data or submit samples to assure the laboratory is maintaining your needed quality.

## INITIAL DATA

- When you send the laboratory your Project Analyte Form and the Cover Letter, you are asking them to provide method information and **DATA**.
- The project should collect data representative of their matrix, ranges, including all analytes, and within acceptable quality limits. It needs to be **BLIND DATA**.

## BLIND DATA

**Blind data** come from quality control or assurance samples in which the laboratory does not know the true value. An example of blind data are those from field replicates, where the lab does not know they are replicates. An example of non-blind samples are laboratory internal spike or blank samples where the lab knows the concentration and they know it is a Quality Control check.

## SINGLE-BLIND SAMPLES

**Single-blind samples** are samples where the lab does not know the true concentrations but _does_ know the sample is a test sample. They may treat it with extra care knowing this.

## DOUBLE-BLIND SAMPLES

- Double-blind samples are samples that the lab does not know the true concentrations AND does not even know the sample is a test sample. They will treat it the same way as any other sample.

## REFERENCE MATERIALS

- Reference Materials are samples that are of a known and certified concentration. They have been tested extensively. Submitting reference materials blindly to the lab is the best test of actual performance.

## SO WHAT DATA DO I COLLECT?

- If the lab has data from blind test samples in the appropriate range and the same method – use that data!
- (such as WS, WP, SRS – the lab knows what these are).
- If they don’t, you’ll have to get some Reference Materials to send to them – blind if possible! BQS can help.

## WHAT DO I DO WITH THE DATA?

- Use the blind data to assess whether or not this laboratory is capable of  providing adequate data. You will verify this periodically with on-going test samples.

## HOW DO I ASSESS THE DATA?

- 1) Does the **recovery** of the initial data match the lab stated variability?
- 2) Are the results within your **expectations**?
- 3) Think if these recoveries were applied to your data. Could you present the environmental sample results in a **publication** as the outcome of good work without explanation?

## NEXT...

- _[Step 2](file:///step2.html)__ on the Laboratory Evaluation Website discusses the collection of data._
- There are _[separate instructions ](file:///howto_lab_dataform.ppt)__for _**laboratories** on the data collection process.

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