N/A or 0

[James_Ball]

lmh,

That definitely makes sense in a research laboratory, because you are needing every bit of information possible. When scientists are the ones using and evaluating the data then you are safe giving interpolated results when they are labeled as such.

I have to be careful in the environmental laboratory here though, because if I can only quantify to 1ppm(calibration curve is becoming quadratic below this point) and I have and estimated peak at 0.02ppm that is barely 5 s/n, I have clients(and state regulating agencies) that want to treat that 0.02ppm result as if it is a certified standard from NIST and base all kinds of decisions on it.

Data end use has to be taken into consideration especially when you have a state auditor who told one of our clients who is a waste water treatment plant operator, "You will make sure that pH value is zero, or I am going to write you a violation".

[lmh]

Yes, James_Ball, couldn't agree more! Even in a research environment I have to be very careful to annotate data very, very clearly with any reason why it should be treated as merely indicative. There is always a risk of over-interpretation.
In fact my view is that those of us in research labs should take the trouble to learn as much as those in regulated labs about proper procedures; we may choose to ignore "rules" and procedures when they're not appropriate, but it should be a conscious choice based on careful thought, not something we drift into through ignorance.
After all, it's not great if huge sums of cash get spent pursuing a research proposal based on a hypothesis derived from an artefact of a bad measurement.
You are totally right. Pity about the pH though, I hope the waste water treatment people didn't take action to conform...

[Steve Reimer]

"I have to be careful in the environmental laboratory here though, because if I can only quantify to 1ppm(calibration curve is becoming quadratic below this point) and I have and estimated peak at 0.02ppm that is barely 5 s/n, I have clients(and state regulating agencies) that want to treat that 0.02ppm result as if it is a certified standard from NIST and base all kinds of decisions on it. "

Too bad you can't report that value in a (semi)realistic way: 0.02ppm, +/- 0.20ppm. That way they may get an idea of error of their ways.

[Peter Apps]

Yes, James_Ball, couldn't agree more! Even in a research environment I have to be very careful to annotate data very, very clearly with any reason why it should be treated as merely indicative. There is always a risk of over-interpretation.
In fact my view is that those of us in research labs should take the trouble to learn as much as those in regulated labs about proper procedures; we may choose to ignore "rules" and procedures when they're not appropriate, but it should be a conscious choice based on careful thought, not something we drift into through ignorance.
After all, it's not great if huge sums of cash get spent pursuing a research proposal based on a hypothesis derived from an artefact of a bad measurement.
You are totally right.

I work in the overlap area of research chemistry and field biology - and I can say without hesitation that chemists should not feel bad about indicative results; field biologists would not know validation if it fell out of a tree on top of them. They don't measure things, they model them.

Peter

[James_Ball]

Yes, James_Ball, couldn't agree more! Even in a research environment I have to be very careful to annotate data very, very clearly with any reason why it should be treated as merely indicative. There is always a risk of over-interpretation.
In fact my view is that those of us in research labs should take the trouble to learn as much as those in regulated labs about proper procedures; we may choose to ignore "rules" and procedures when they're not appropriate, but it should be a conscious choice based on careful thought, not something we drift into through ignorance.
After all, it's not great if huge sums of cash get spent pursuing a research proposal based on a hypothesis derived from an artefact of a bad measurement.
You are totally right. Pity about the pH though, I hope the waste water treatment people didn't take action to conform...

Luckily they didn't. They knew better, and the auditors boss happened to be there too. I imagine they all just shook their heads as we did when an auditor asked us why we didn't have an MDL study on file for everything we do, including pH and odor.