RE: When does correlation imply causation?

2001-12-10 Thread David Heiser
-Original Message- Dennis Roberts makes a good point here >i repeat ... the r value shows the extent to which a straight line (in a 2 >variable problem) can pass through a scatterplot and, be close TO the data >points >in that sense, r is an index value for the extent to which a straig

Re: When does correlation imply causation?

2001-12-07 Thread Jay Warner
out. Jay [EMAIL PROTECTED] wrote: > Classic study: Correlation between local stork population and local births. > > -Original Message- > From: Stu [mailto:[EMAIL PROTECTED]] > Sent: Thursday, December 06, 2001 1:08 AM > To: [EMAIL PROTECTED] > Subject: Re: When does co

RE: When does correlation imply causation?

2001-12-07 Thread jim clark
Hi On 6 Dec 2001, David Heiser wrote: > Most of the focus is on structural equation modeling (SEM). For > statisticians, a quick referral to Jim Steiger's article "Driving Fast in > Reverse" in JASA March 2001, p331-p338 (if you have it around) is a quick > discourse on SEM and the inherent probl

RE: When does correlation imply causation?

2001-12-06 Thread David Heiser
The issue of causality from the results of fitting a model to data has been a major topic on SEMNET over the last many years. If anyone wishes to pursue ideas on this and related issues, subscribe to [EMAIL PROTECTED] Most of the focus is on structural equation modeling (SEM). For statisticians,

RE: When does correlation imply causation?

2001-12-06 Thread hdaley
Classic study: Correlation between local stork population and local births. -Original Message- From: Stu [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 06, 2001 1:08 AM To: [EMAIL PROTECTED] Subject: Re: When does correlation imply causation? > My favorite original example is

Re: When does correlation imply causation?

2001-12-06 Thread Art Kendall
This is a multi-part message in MIME format. --E98CFE9DA7C53331DB22D947 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Is it a fair interpretation of what you are saying to say that the process of correlating phenomena needs to be distinguished from the va

Re: When does correlation imply causation?

2001-12-06 Thread Dennis Roberts
i repeat ... the r value shows the extent to which a straight line (in a 2 variable problem) can pass through a scatterplot and, be close TO the data points in that sense, r is an index value for the extent to which a straight line MODEL fits the data ... knowing how the dots on the scatterpl

Re: When does correlation imply causation?

2001-12-06 Thread Alex Yu
Whether we can get causal inferences out of correlation and equations has been a dispute between two camps: For causation: Clark Glymour (Philosopher), Pearl (Computer scientist), James Woodward (Philosopher) Against: Nancy Cartwright (Economist and philosopher), David Freedman (Mathematici

Re: When does correlation imply causation?

2001-12-05 Thread Stu
> My favorite original example is the correlation between number of > annual murders in a city and number of books in its libraries. > Students have no trouble seeing that the two are going to have a > fairly high correlation coefficient(*), but murders don't make > people read and books don't mak

Re: When does correlation imply causation?

2001-12-05 Thread Stan Brown
Dennis Roberts <[EMAIL PROTECTED]> wrote in sci.stat.edu: >personally, i think it is dangerous in ANY case to say that r = cause ... Hear, hear! My favorite original example is the correlation between number of annual murders in a city and number of books in its libraries. Students have no tro

Re: When does correlation imply causation?

2001-12-05 Thread Rich Ulrich
On 5 Dec 2001 08:52:41 -0800, [EMAIL PROTECTED] (Dennis Roberts) wrote: > correlation NEVER implies causation ... That is true - in the strong sense, and - in formal logic, and - as a famous quotation among researchers. (And, reported as wrongly contrasted to 'ANOVA'.) Or, correlation always

RE: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
what if we see, from the side, one person on the right swing his/her fist ... and, as the fist arrives at what appears to be the impact point of the face of a person on the left ... that IMMEDIATELY the person on the left falls backwards and down now, we do this over and over again ... and obs

RE: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
perhaps the problem here is with the word ... "cause" say i put in a column some temps in F ... then use the F to C formula ... and get the corresponding C values ... then i do an r between the two and find 1.0 now, is the formula the "cause" of the r of 1? maybe we might see it as a cause bu

RE: When does correlation imply causation?

2001-12-05 Thread Wuensch, Karl L
Dennis warns "the problem with this is ... does higher correlation mean MORE cause? lower r mean LESS cause? in what sense can think of cause being more or less? you HAVE to think that way IF you want to use the r value AS an INDEX MEASURE of cause ..." Dennis is not going to like this, since he

Re: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
At 07:36 AM 12/5/01 -0500, Karl L. Wuensch wrote: > Accordingly, I argue that correlation is a necessary but not a > sufficient condition to make causal inferences with reasonable > confidence. Also necessary is an appropriate method of data > collection. To make such causal infer

Re: When does correlation imply causation?

2001-12-05 Thread Dennis Roberts
correlation NEVER implies causation ... and i agree with mike totally At 09:01 AM 12/5/01 -0600, Mike Granaas wrote: >We really need to emphasize over and over that it is the manner in which >you collect the data and not the statistical technique that allows one to >make causal inferences. > >M

Re: When does correlation imply causation?

2001-12-05 Thread Mike Granaas
On Wed, 5 Dec 2001, Karl L. Wuensch wrote: > > > So why is it that many persons believe that one can make causal inferences >with confidence from the results of two-group t tests and ANOVA but not with the >results of correlation/regression techniques. I believe that this delusio

When does correlation imply causation?

2001-12-05 Thread Karl L. Wuensch
ows, but is long.   When Does Correlation Imply Causation?     It is not rare for researchers and students to confuse (1) correlation as a statistical technique with (2) nonexperimental data collection methods, which are also often described as “correlational.”  For example, a doctor