regression question

[johnron]

hello!!
iwant to examine what are the factors that influence the change in the profits of firms (thats my Y in the regression).

My independent variables are – sales; year; big (examine by log on total assets)​

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Sales – should I check the change from one year to another or should I just insert the numeric value of sales each year?​

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Year – should I make a dummy variable for each year or should I do it like this:​

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2010 – 0​

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2011 – 1​

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2012 – 2​

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2013 -3​

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Big – I want to check the difference between small to big firms​

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Should I do it with a dummy variable or should I use the numeric values of the log(total assets)?

Thanks in advance!

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[anglais428]

The year is not really a variable in that each year is one different from the last. I would remove it. Dummy variables should really on be 0 or 1. As with all regeression you can trial and error to get a good model. I would start with sales and total assets.