dummy variables

[diana.s]

Dear all,
Can someone help me, I have some troubles with dummy variables. I have some series of exchange rates, with big fluctuations in the last 3 years due to the crisis. My question is: I should use dummies for the entire period of the financial crisis (2007-2011) or just for the period with big fluctuations for the exchange rate?

Thank you all.
Diana

[k0rnik]

It's more theoretical than technical question. I'm not good in EViews, but I'm fell strong in economics and finance. In my opinion you should use dummy variables for all period. In other case how you going to explain it ? It's better to have strong theoretical reason. Eg. show that you include dummy variables for period when SMA 200 ( days) cut SP500 daily line, that's will be your indication of "crisis"