Decomposition for log-linear model - AnalyticBridge2021-06-25T04:29:54Zhttps://www.analyticbridge.datasciencecentral.com/forum/topics/decomposition-for-log-linear-model?feed=yes&xn_auth=noHey Bishu!! Long time.. I was…tag:www.analyticbridge.datasciencecentral.com,2019-07-01:2004291:Comment:3931152019-07-01T18:07:50.984ZArunhttps://www.analyticbridge.datasciencecentral.com/profile/Arun
<p>Hey Bishu!! Long time.. I was pretty much looking for something similar since I ended up doing log-linear for a market mix project. </p>
<p>As far as I can tell, there's no easy way to land at decompositions for a log-linear model. Log transformed models lose all relations to the original variable, and the multiplicity of the explanatory vars end up making it difficult to say what % of something caused something. Elasticities are available ofcourse.</p>
<p>There's 2 approx. methods though…</p>
<p>Hey Bishu!! Long time.. I was pretty much looking for something similar since I ended up doing log-linear for a market mix project. </p>
<p>As far as I can tell, there's no easy way to land at decompositions for a log-linear model. Log transformed models lose all relations to the original variable, and the multiplicity of the explanatory vars end up making it difficult to say what % of something caused something. Elasticities are available ofcourse.</p>
<p>There's 2 approx. methods though that I came across that might help - 'Purging Method' and 'Delta Method' that help approximate the % contribution.</p>
<p>(And I can tell the other person who commented has no idea what you're asking! Lol.)</p>
<p></p>
<p>Best,</p>
<p>Arun (let's see if you recognize who this is!)</p> Dear Biswajit,
Good evening.…tag:www.analyticbridge.datasciencecentral.com,2014-12-05:2004291:Comment:3152132014-12-05T13:58:38.612ZSagar Diwakar Uparkarhttps://www.analyticbridge.datasciencecentral.com/profile/SagarDiwakarUparkar
Dear Biswajit,<br />
Good evening. Your statement has ambiguity. If you are building regression equation using independent variables to find dependent variable then you'll have the value and proportion of each factor playing role in it. Also, SAS will give you coefficient value too. Apart from this if you require forecasted value of independent variables to forecast dependent then use time series. I hope, I'd answered your question. If I misunderstood then please give little more clarity about your…
Dear Biswajit,<br />
Good evening. Your statement has ambiguity. If you are building regression equation using independent variables to find dependent variable then you'll have the value and proportion of each factor playing role in it. Also, SAS will give you coefficient value too. Apart from this if you require forecasted value of independent variables to forecast dependent then use time series. I hope, I'd answered your question. If I misunderstood then please give little more clarity about your purpose.<br />
<br />
Regards,<br />
Sagar.