Dear all,
I am trying to estimate a fertility curve, using the data in the attached workfile.
I am trying to estimate the following equation using least squares (other estimation methods also do not yield results).
equation eq1.ls fertility=c(1)*(c(2)/c(3))*(c(3)/age)^(3/2)*exp(-(c(2))^2*(c(3)/age+age/c(3)-2))
I keep getting an error message saying I have insufficient observations, which I don't understand. Any assistance would be greatly appreciated.
Insufficient observations
Moderators: EViews Gareth, EViews Moderator
Insufficient observations
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- Fertility_eviews.WF1
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- Non-normality and collinearity are NOT problems!
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Re: Insufficient observations
EViews starts estimation with whatever is stored in the c vector. In your case, this is causing some division by zero. Try saying
before you start the estimation.
Code: Select all
c = 1
Re: Insufficient observations
startz wrote:EViews starts estimation with whatever is stored in the c vector. In your case, this is causing some division by zero. Try sayingbefore you start the estimation.Code: Select all
c = 1
Many thanks Startz, works perfectly.
Re: Insufficient observations
Dear all,
I've encountered the same issue, so your answer was very useful - many thanks for that.
Based on the workfile attached in this thread, I have a question concerning the starting point values. I have set the following equation and starting point values, which should be close enough to the actual curve:
param c(1) 1 c(2) -.15 c(3) 30 c(4) 8
equation eq1.ls fertility=2*c(4)^(-1)*exp(-(age-c(3))/c(4))/((1+exp(-(age-c(3))/c(4)))^2*(1+exp(-c(1)*((age-c(3))/c(4))-c(2)*((age-c(3))/c(4))^3)))
However, when I change these values, I do not get any changes in the estimated coefficients (which I would expected). Also, even if I close and open the program, I get convergence all the time in the same number of iterations. I wouldn't have expected this -maybe I'm thinking in terms of the "Solver" addin of Excel, and that's confusing me (relatedly, the estimation I get through Solver by minimizing the SSR is much closer to the actual figure compared to what I get in Eviews).
Any help would be highly appreciated.
Thanks in advance.
I've encountered the same issue, so your answer was very useful - many thanks for that.
Based on the workfile attached in this thread, I have a question concerning the starting point values. I have set the following equation and starting point values, which should be close enough to the actual curve:
param c(1) 1 c(2) -.15 c(3) 30 c(4) 8
equation eq1.ls fertility=2*c(4)^(-1)*exp(-(age-c(3))/c(4))/((1+exp(-(age-c(3))/c(4)))^2*(1+exp(-c(1)*((age-c(3))/c(4))-c(2)*((age-c(3))/c(4))^3)))
However, when I change these values, I do not get any changes in the estimated coefficients (which I would expected). Also, even if I close and open the program, I get convergence all the time in the same number of iterations. I wouldn't have expected this -maybe I'm thinking in terms of the "Solver" addin of Excel, and that's confusing me (relatedly, the estimation I get through Solver by minimizing the SSR is much closer to the actual figure compared to what I get in Eviews).
Any help would be highly appreciated.
Thanks in advance.
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