Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: st: RE: Principal Components Analysis with count data


From   Cameron McIntosh <[email protected]>
To   STATA LIST <[email protected]>
Subject   RE: st: RE: Principal Components Analysis with count data
Date   Fri, 14 Aug 2009 10:06:29 -0400

True about Mplus, but I think what Jason is looking for is a formative model that rolls up the items into a composite harm index, rather than a reflective modeling framework that uses the items as indicators of an underlying latent harm construct. For that, generalized structured components analysis or partial least squares modeling might be better options: 
 
http://www.sem-gesca.org/reference.php
http://faculty.chass.ncsu.edu/garson/PA765/pls.htm 
(see PLS path modeling links near the bottom of the second link, that's what you'd want) 
 
Cam

----------------------------------------
> From: [email protected]
> To: [email protected]
> Date: Fri, 14 Aug 2009 09:50:13 -0400
> Subject: st: RE: Principal Components Analysis with count data
>
> After reading a description of your data I'd suggest you might want to take a look at the MPlus program. It allows estimation of a wide range of models, including both exploratory and confirmatory factor analysis with continuous, count, ordered discrete, and dichotomous observed indicators.
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Jason Ferris
> Sent: Thursday, August 13, 2009 7:09 PM
> To: [email protected]
> Subject: st: Principal Components Analysis with count data
>
> Nick,
> Thank you for your added comments; it gives me hope not to have to categorise the data and use MCA methods.
>
> To address your third point:
>
> 3. Whether PCA will work well does depend on what you expect it to do ideally, which is not clear in the question.
>
> We have a survey question of 2600 people. Who answer 14 questions about varying degrees of community harms. Each question collects 'how many times did this happen to you in the previous 12 months'. So we collect counts of all 14 questions - ranging from 0 to 365 (indicating at least once a day). The typical pattern for most of the items are as follows:
> mean 
> We are hoping to reduce the 14 questions to 3/4 main components to use as outcome variables for further analysis.
>
> If we go down the MCA approach we would probably group the data 0, 1/5,
> 6+.
>
> HTH,
> Jase
>
> ------------------------------------------
> DISCLAIMER: This message (including any attachments) is intended solely for the addressee(s) named and may contain confidential or privileged information.
> If you are not the intended recipient, please delete it and notify the sender.
> Views expressed in this message are those of the individual sender,and are not necessarily the views of the Turning Point Alcohol and Drug Centre Inc (ABN: 17 302 055 629).
>
> Turning Point Alcohol and Drug Centre Inc
>
> Although this message and any attachments have been scanned for viruses by 'Trend Micro InterScan' at the time of sending, you are advised to rescan on receipt.
>
> The whole or parts of this email may be subject to copyright of Turning Point Alcohol and Drug Centre Inc (ABN: 17 302 055 629), and/or third parties.
> You can only re-transmit, distribute or use the material if you are authorised to do so.
>
> Please consider the environment before printing this email or attachments.
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
> This e-mail and any files transmitted with it are confidential and intended solely for the use of the individual
> or entity to whom they are addressed. If you are not the intended recipient, you are hereby notified
> that any disclosure, copying, distribution or taking of any action in reliance on the information contained in
> this e-mail is prohibited. If you have received this e-mail in error, please notify sender by reply e-mail and
> delete this message and any attachment(s) immediately. Thank you for your consideration in this matter.
>
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
_________________________________________________________________
Stay on top of things, check email from other accounts!
http://go.microsoft.com/?linkid=9671355
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2024 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index