The Inaccuracy of Digital Meters

[wiltw]

Gee, can't my slide rule indicate the value of pi to 3.14159. . . . . . . .

It CAN, but can your eye detect the difference between 3.14159 and 3.142857 (the nominal value, 22/7) displayed on the slide rule?!
It is, after all, an analog device and not digital (except for it being held by your digits!

 

[cowanw]

In this case I think everyone agrees that it was the guy fault. However this is not because the digital readout. The readout would clearly show that it has the resolution of 10mg (that is what it can display and not speaking of accuracy) and if he want to measure 105mg with that is his fault. It's not the digital display that gives the false sense of accuracy. It's more likely that such a guy would have tried to guess between the mark when he used a scale with analog pointer.

Not me; Not yet. I would like to know what the drug was and whether a 30% overdose really is a lethal dose. Not many drugs (? any) have that acute a lethal to therapeutic dose range. Most are many 100%'s greater.

 

[Deleted member 88956]

Not me; Not yet. I would like to know what the drug was and whether a 30% overdose really is a lethal dose. Not many drugs (? any) have that acute a lethal to therapeutic dose range. Most are many 100%'s greater.

But this is about using a tool in a foolish way, which he is at fault. Whether he did the killing is arguably another matter.

 

[AgX]

I would like to know what the drug was and whether a 30% overdose really is a lethal dose. Not many drugs (? any) have that acute a lethal to therapeutic dose range. Most are many 100%'s greater.

I asked that myself. However the actual error he made may even have been greater. The prosecution had it about overdoses of a multiple each.
And seemingly the idea of the prosecution was just to prove the lack expertise of the accused.

 

[AgX]

The man was sentenced for negligent homicide, with the negligent weighing operation at center of the argumentation of the court.

 

[Eric Rose]

When I do rifle and pistol cartridge reloading I calibrate my scales using certified weights. I also double check the calibration as I go along. Things that go bang make me VERY careful. While I measure things down to a tenth of a grain I fully realize like Ag has said the last digit on the digital meter is nothing more than a "suggestion". I've been a target shooter since my teens.

When it comes to photography I am not near as fussy.

 

[BrianShaw]

But the suppliers are to blame too, for negligence or even intent.

With intent I mean those who emphasize the several-digit readout, but give no hint at tolerances.
With negligence I refer to manufacturers like the one of this scale, who not add features. As clearly stating the max error next to the display and blocking the display at loads below the minimum one.

... and what about this aspect?

 

[AgX]

Good point.
The jury seemingly expects from a person doing such difficile treatment (by selfmade infusions of a non-clinically tested chemical, which showed to be very criticil in dosage in animal testing) a higher degree af alertness, which includes reading the manual/data sheet.

 

[BrianShaw]

Good point.
The jury seemingly expects from a person doing such difficile treatment (by selfmade infusions of a non-clinically tested chemical, which showed to be very criticil in dosage in animal testing) a higher degree af alertness, which includes reading the manual/data sheet.

I guess I’m a real hard-ass on this topic, but that expectation is a normal expectation of any competent equipment user. Often skipped but I don’t cut anyone slack for that kind of laziness, or arrogance, or foolishness... however one might want to classify it. The jury finding was a no-brainer.

 

[BrianShaw]

What really surprised me is that they actually let it go to court rather than settling by pleading guilty.

 

[AgX]

In Germany and other European countries the accused cannot settle things with the prosecutor in advance in cases of severity.
In general the system of criminal justice in Germany is very different from that of the USA.

But this all is going off topic.

 

[BrianShaw]

Good information; I was unaware. Not too off topic...

 

[Luckless]

It CAN, but can your eye detect the difference between 3.14159 and 3.142857 (the nominal value, 22/7) displayed on the slide rule?!
It is, after all, an analog device and not digital (except for it being held by your digits!

Clearly the answer is to build a bigger, more accurate slide rule...

[I'm totally not wondering how much the girlfriend will yell at me if I make a ring-rule as replacement for the dining room table.]

 

[AgX]

Clearly the answer is to build a bigger, more accurate slide rule...

There is such already:
https://www.photrio.com/forum/threads/slide-rules.163413/page-3#post-2129708

 

[Eric Rose]

In Germany and other European countries the accused cannot settle things with the prosecutor in advance in cases of severity.
In general the system of criminal justice in Germany is very different from that of the USA.

But this all is going off topic.

I like this approach. Too many plea deals in NA. In many cases people who have done nothing wrong are made to feel they have no way out but to plea to a lesser charge than what they are being threatened with just to have some hope of ever getting out of jail. It's a sick system all around.

 

[MattKing]

I like this approach. Too many plea deals in NA. In many cases people who have done nothing wrong are made to feel they have no way out but to plea to a lesser charge than what they are being threatened with just to have some hope of ever getting out of jail. It's a sick system all around.

Eric:
I understand where you are coming from, but I've got another perspective, because I've worked with clients who chose to plead guilty, and as a result both they and the populace in general benefited from that choice. The populace benefits from certainty, prompt resolution, reduced cost and reduction of suffering for victims.
One of the things that most people don't realize that, at least in Canada, pleas don't generally happen until after there has been extensive disclosure of the Crown's case against the accused.
And in most cases, if there is going to be a trial, it will be before an experienced jurist, with a lot of experience working with "beyond a reasonable doubt", rather than inexperienced jurors.
Some of the absolutely best results I ever helped my clients obtain were sentences after a guilty plea.
And like most counsel who have appeared in criminal law courts, I certainly have helped the court reach a not guilty result.
Don't be misled by what you see on TV - most pleas happen after either careful deliberation or, in some cases, when the evidence against is overwhelming, and the offer from Crown Counsel is appropriately fair, in light of the accused accepting responsibility.

 

[Ariston]

I guess I’m a real hard-ass on this topic, but that expectation is a normal expectation of any competent equipment user. Often skipped but I don’t cut anyone slack for that kind of laziness, or arrogance, or foolishness... however one might want to classify it. The jury finding was a no-brainer.

This is especially true of a physician. I use laser measures in my line of work, and I always check new equipment against an actual tape. There is no excuse for a doctor to simply assume a scale is right. In fact, a competent doctor would assume it is wrong until he can prove otherwise.

Then again, the term "competent doctor" is a bit of any oxymoron.

 

[Sirius Glass]

I like this approach. Too many plea deals in NA. In many cases people who have done nothing wrong are made to feel they have no way out but to plea to a lesser charge than what they are being threatened with just to have some hope of ever getting out of jail. It's a sick system all around.

Please explain what the Hell this has to do with inaccuracies of either analog or digital light meters. And exactly how pleas bias the exposure.

 

[MattKing]

Please explain what the Hell this has to do with inaccuracies of either analog or digital light meters. And exactly how pleas bias the exposure.

The thread is about a criminal charge arising out of a failure to use equipment properly.

 

[Eric Rose]

Eric:
I understand where you are coming from, but I've got another perspective, because I've worked with clients who chose to plead guilty, and as a result both they and the populace in general benefited from that choice. The populace benefits from certainty, prompt resolution, reduced cost and reduction of suffering for victims.
One of the things that most people don't realize that, at least in Canada, pleas don't generally happen until after there has been extensive disclosure of the Crown's case against the accused.
And in most cases, if there is going to be a trial, it will be before an experienced jurist, with a lot of experience working with "beyond a reasonable doubt", rather than inexperienced jurors.
Some of the absolutely best results I ever helped my clients obtain were sentences after a guilty plea.
And like most counsel who have appeared in criminal law courts, I certainly have helped the court reach a not guilty result.
Don't be misled by what you see on TV - most pleas happen after either careful deliberation or, in some cases, when the evidence against is overwhelming, and the offer from Crown Counsel is appropriately fair, in light of the accused accepting responsibility.

At least in Canada I feel things are a bit better than the US.

 

[Deleted member 88956]

Eric:
I understand where you are coming from, but I've got another perspective, because I've worked with clients who chose to plead guilty, and as a result both they and the populace in general benefited from that choice. The populace benefits from certainty, prompt resolution, reduced cost and reduction of suffering for victims.
One of the things that most people don't realize that, at least in Canada, pleas don't generally happen until after there has been extensive disclosure of the Crown's case against the accused.
And in most cases, if there is going to be a trial, it will be before an experienced jurist, with a lot of experience working with "beyond a reasonable doubt", rather than inexperienced jurors.
Some of the absolutely best results I ever helped my clients obtain were sentences after a guilty plea.
And like most counsel who have appeared in criminal law courts, I certainly have helped the court reach a not guilty result.
Don't be misled by what you see on TV - most pleas happen after either careful deliberation or, in some cases, when the evidence against is overwhelming, and the offer from Crown Counsel is appropriately fair, in light of the accused accepting responsibility.

What I hate about lawyers is that somehow they take oath to protect accused from all charges no matter what the evidence is, and they view that as their success story to boot. And I don't know of a single system where actual justice is served regularly. Pleas make me sick in all serious cases, but far worse are those who did commit an atrocious crime getting off on a technicality. I don't know what kind of person can sleep knowing from evidence alone his client committed, saw all suffering, yet was beyond extatic to serve victims absolute vindication of his client on an irrelevant procedural misdeed.

The problem with justice everywhere is that it is controlled by too many who do not support justice in the first place.

 

[MattKing]

What I hate about lawyers is that somehow they take oath to protect accused from all charges no matter what the evidence is, and they view that as their success story to boot. And I don't know of a single system where actual justice is served regularly. Pleas make me sick in all serious cases, but far worse are those who did commit an atrocious crime getting off on a technicality. I don't know what kind of person can sleep knowing from evidence alone his client committed, saw all suffering, yet was beyond extatic to serve victims absolute vindication of his client on an irrelevant procedural misdeed.

The problem with justice everywhere is that it is controlled by too many who do not support justice in the first place.

I best not respond fully, as this will change from just an aside to a complete derailment of the thread.
What I will say though is that, despite what you might think, both defence counsel and prosecutors are actually working toward the same goal - the preservation of justice. A criminal law allegation that is incapable of withstanding fair challenge is not a thing that should normally stand.

 

[alanrockwood]

Let me focus on the case that introduced the thread. First, I want to say that I do not know about the particulars of the case. However, there is a point that everyone seems to have missed, and that is whether the accused was following the standard operating procedure (SOP) for preparation of the dose. I worked for about 16 years in the medical field, specifically clinical laboratory science. Clinical laboratory science is not necessarily a perfect analogy to preparing a dose of medication, but for purposes of discussion I am going to assume that the analogy is quite close.

In my profession every laboratory method was strictly specified by an SOP. Let us assume that the preparation of a therapeutic dose is similarly specified. (Someone correct me if you know this to be wrong.) In this case, if the type of scales used to prepare the dose are specified in the SOP, and if the amount of the dose was within the SOP specification, and if the person preparing the dose followed the SOP (i.e. used the scales specified at the amount specified in the SOP), then the person who prepared the dose was not at fault. The fault would be with the person who wrote the SOP as well as everyone who signed off on the SOP.

There is also another subtlety. In my profession the calibration of all scales had to be checked on a specified schedule, such as yearly. Also, any instrument that had been exposed to some kind of change would also need to undergo some kind of re-validation. For example, if an instrument were moved from one location to another a re-validation would be required. I don't recall if scales fell under this regulation, but I would be surprised if they did not.

An additional subtlety relates to training. I think this might have been mentioned in the thread already, but if so I am mentioning it again. If the SOP specified the use of a certain scale and that the scale be operating within specific parameters, then the organization is responsible to train the person preparing the dose on these requirements. If proper training was not carried out, including a proficiency test, then logically the fault lies with the organization, not necessarily with the person preparing the dose.

Finally, I would like to briefly mention error budgets. I won't go into detail, but a proper analysis of the error budget for a measurement folds both accuracy and precision together into an overall error budget, and typically the error budget is given by a graph that encompasses the allowable measurement range.

 

[AgX]

Let me focus on the case that introduced the thread. First, I want to say that I do not know about the particulars of the case. However, there is a point that everyone seems to have missed, and that is whether the accused was following the standard operating procedure (SOP) for preparation of the dose. I worked for about 16 years in the medical field, specifically clinical laboratory science. Clinical laboratory science is not necessarily a perfect analogy to preparing a dose of medication, but for purposes of discussion I am going to assume that the analogy is quite close.

-) The accused in this case was a "Heilpraktiker". This is a german profession that needs NO formal training at all. One just has to pass a test at the municipal department of health. In contrast to neighbouring countries a german Heilpraktiker may even apply invasive treatment as an infusion of a chemical.

-) From my experience at medical schools I expect that good measuring procedures are not taught within the training of medical doctors either...

 

[wiltw]

Clearly the answer is to build a bigger, more accurate slide rule...

[I'm totally not wondering how much the girlfriend will yell at me if I make a ring-rule as replacement for the dining room table.]

Making it longer would not improve your ability to distinguish the difference between 3.14159 and 3.142857 ...unless the graduations were available engraved to 3 digits right of the decimal.
So domestic tranquility will continue in your household.