CSI and cadaver dogs - some facts and statistics.

[G-Unit]

I don't understand how you came up with those percentages. Could you walk me through one or two examples so that I can get the idea?

One point that I believe skews the discussion is the assumption that "cadaver" scent necessarily means a deceased human (or pig).

Something I'm still not sure about is whether "human decomposition" scent is a euphemism or whether it is a more accurate term depending on the dog's training. I suspect the latter as we already know that Eddie reacted to dried blood from a living human being.

If a different dog had been solely trained on post-mortem human remains and had never reacted to decomposing material from a living human, then I'd find that issue clearer.

In other words, whatever the argument about percentages of accuracy, if a dog reacts to fruit, in the absence of corroborative information, you still don't know whether he's correctly alerted to an orange or a pear.

My conclusion being that Keela only reacts to bananas (and she may or may not always be accurate). Eddie reacted to fruit and if he reacted, Keela was wheeled in to see if she could detect a banana. Where Keela does not identify a banana, and Eddie reacts to fruit, how does anyone know which type in the absence of identifiable fruit pips or kernels?

Eddie alerted to cadaver scent and blood. If he alerted Keela was used. If she alerted, it was assumed that there was blood present. if she didn't the alert was assumed to be cadaver scent.

[Mr Gray]

Eddie alerted to cadaver scent and blood. If he alerted Keela was used. If she alerted, it was assumed that there was blood present. if she didn't the alert was assumed to be cadaver scent.

there's a lot of assuming going on..

[Carana]

Eddie alerted to cadaver scent and blood. If he alerted Keela was used. If she alerted, it was assumed that there was blood present. if she didn't the alert was assumed to be cadaver scent.

Assumed being the operative word.

Nowhere have I seen Grime state in the files whether Eddie would react to the scent of dried blood in the absence of a physical source or not.

I haven't seen anything to indicate whether Grime wrote up his notes on Eddie's alert to sex tissues in Jersey at the time of the alert or whether he waited for Keela's reaction before deciding that Eddie must have reacted to a speck of blood.

I appreciate people who understand statistics far better than I will ever do trying to work out accuracy percentages, but my query is somewhat more basic...

[slartibartfast]

I don't understand how you came up with those percentages. Could you walk me through one or two examples so that I can get the idea?

One point that I believe skews the discussion is the assumption that "cadaver" scent necessarily means a deceased human (or pig).

Something I'm still not sure about is whether "human decomposition" scent is a euphemism or whether it is a more accurate term depending on the dog's training. I suspect the latter as we already know that Eddie reacted to dried blood from a living human being.

If a different dog had been solely trained on post-mortem human remains and had never reacted to decomposing material from a living human, then I'd find that issue clearer.

In other words, whatever the argument about percentages of accuracy, if a dog reacts to fruit, in the absence of corroborative information, you still don't know whether he's correctly alerted to an orange or a pear.

My conclusion being that Keela only reacts to bananas (and she may or may not always be accurate). Eddie reacted to fruit and if he reacted, Keela was wheeled in to see if she could detect a banana. Where Keela does not identify a banana, and Eddie reacts to fruit, how does anyone know which type in the absence of identifiable fruit pips or kernels?

It was OBs percentages (using a top of his range percentage for Blood Dog as I would say it is very mainstream).

[Carana]

It was OBs percentages (using a top of his range percentage for Blood Dog as I would say it is very mainstream).

That's ok... you could be arguing about the finer points of astrophysics when my concern would be whether I was likely to be hit by a meteor in the near future or not.

Back to my point though, unless anyone has further information, the outcome of the statistics is assumed to relate to a defined conclusion (i.e. a dead body).

And I simply can't find anything relating to that dog to make me assume that - if his alert was correct - that he correctly alerted to a "cadaver".

[slartibartfast]

That's ok... you could be arguing about the finer points of astrophysics when my concern would be whether I was likely to be hit by a meteor in the near future or not.

Back to my point though, unless anyone has further information, the outcome of the statistics is assumed to relate to a defined conclusion (i.e. a dead body).

And I simply can't find anything relating to that dog to make me assume that - if his alert was correct - that he correctly alerted to a "cadaver".

It is the most likely source of the scent.

[Carana]

It is the most likely source of the scent.

What is and according to whom?

[slartibartfast]

What is and according to whom?

The dogs alert to the scent produced by a decaying body (or decaying pig).

[OxfordBloo]

The dogs alert to the scent produced by a decaying body (or decaying pig).

Keela alerts to blood not cadaver
Eddie alerts to blood and or cadaver.

Both can give false positive nd false negative alerts.

[Carana]

The dogs alert to the scent produced by a decaying body (or decaying pig).

- Has the potential residual scent of a bloodied plaster been eliminated?
- Have residual scents of irrelevant activities likely to occur in the master bedroom of a holiday flat been excluded?
- Have all the occupants post-disappearance been interviewed?
- Have the furnishings been excluded as a source of potential contaminant?

Isn't it somewhat simplistic to assume that even a correct alert by Eddie = dead body?

[pathfinder73]

Keela alerts to blood not cadaver
Eddie alerts to blood and or cadaver.

Both can give false positive nd false negative alerts.

Then you can name one missing case where Eddie has alerted to cadaver scent and the person has turned up alive. That should be easy peasy for a self-proclaimed dog expert like you.

[G-Unit]

Keela alerts to blood not cadaver
Eddie alerts to blood and or cadaver.

Both can give false positive nd false negative alerts.

And no-one can prove that their alerts were false positives, no matter how much they try.

[Carana]

Then you can name one missing case where Eddie has alerted to cadaver scent and the person has turned up alive. That should be easy peasy for a self-proclaimed dog expert like you.

As there is very little information on the identities of the victims of unknown fate in cases on which he did work (protected according to an FOI response), that might be somewhat difficult to verify.

[Mr Gray]

Then you can name one missing case where Eddie has alerted to cadaver scent and the person has turned up alive. That should be easy peasy for a self-proclaimed dog expert like you.

that's  a very silly question...so if we take PDL whose cadaver scent was eddies supposedly alerting to...

[Mr Gray]

And no-one can prove that their alerts were false positives, no matter how much they try.

we don't have to try anything ...grime does not confirm that the alerts ARE to cadaver...