[Basta-users] not finding declining mortality

[Colchero, Fernando]

Hello Cliff,

   Looking at the life table you sent, although between ages 0 and 4 there seems to be declining mortality, at age 5 all of the remaining 33 individuals die. If there were negative senescence over the entire life course, then a few individuals should have lived much longer, which is not the case. Maybe in this case a better model should be a Gompertz with bathtub shape.

  Best,

  Fernando


______________________________________________
 
Fernando Colchero

Max Planck Institute for Demographic Research
Konrad Zuse Str. 1, 18057, Rostock, Germany
Tel:  +49 (0) 381 2081 113
Fax: +49 (0) 381 2081 529
E-mail: Colchero at demogr.mpg.de
______________________________________________





On Nov 16, 2011, at 12:00 AM, Cliff Cunningham wrote:


	Dear Basta,

	Basta isn't finding declining mortality in a sample dataset where the lifetable output by Basta shows declining qx for 4 years in a row (0.78, 0.57, 0.36,0.29).  I input a negative value for b1 (beta) as a prior, but it still found a positive Gompertz fit.  

	Here is the lifetable and the Gompertz parameters.  I'm not sure where the signal for increasing mortality comes from here.  I am using your default.basta file when I run these.  The result is the same with the Makeham shape.

	


Coefficients:	 										
   Estimate  StdErr Lower95%CI Upper95%CI SerAutocor UpdateRate PotScaleReduc	 					
b0	 -1.444	 0.17489	 -1.788	 -1.1039	 0.45801	 0.6506	 1.0003	 				
b1	 0.31	 0.07555	 0.1642	 0.459	 0.47704	 0.6506	 1.0008	 				
pi	 0.4108	 0.03974	 0.3366	 0.4901	 -0.01783	 1	 0.9996	 				
												
Convergence:	 										
Appropriate convergence reached for all parameters.	 							
												
DIC:	 											
591.5485	 											
> MakeLifeTable(FemalesDecSimulation79onlyBrthsAg0GOMak$Xq[1,], ax = 0.5, n = 1)	 					
  StartAge EndAge  lx  dx        mx  ax        qx        px    Lx    Tx        ex	 						
1	 0	 1	 768	 601	 1.2855615	 0.5	 0.7825521	 0.2174479	 467.5	 702	 0.9140625	 
2	 1	 2	 167	 95	 0.7949791	 0.5	 0.5688623	 0.4311377	 119.5	 234.5	 1.4041916	 
3	 2	 3	 72	 26	 0.440678	 0.5	 0.3611111	 0.6388889	 59	 115	 1.5972222	 
4	 3	 4	 46	 13	 0.3291139	 0.5	 0.2826087	 0.7173913	 39.5	 56	 1.2173913	 
5	 4	 5	 33	 33	 2	 0.5	 1	 0	 16.5	 16.5	 0.5	 


	
	All the best!

	    Cliff Cunningham


	        Professor
	Biology Department
	     Duke University
	        130 Science Drive
	Durham NC 27708
	
	Phone 919-660-7356
	

	http://www.biology.duke.edu/cunningham




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