--- imach096d/doc/imach.htm 2002/03/06 18:56:09 1.6 +++ imach096d/doc/imach.htm 2002/03/11 22:26:00 1.10 @@ -1,3 +1,4 @@ +
@@ -6,6 +7,13 @@ content="text/html; charset=iso-8859-1">Version -0.7, February 2002
+0.71a, March 2002This is a comment. Comments start with a '#'.
@@ -321,9 +327,7 @@ lineIntercept and age are systematically included in the model. -Additional covariates can be included with the command
+Additional covariates can be included with the command:model=list of covariates@@ -369,6 +373,19 @@ Additional covariates can be included wi the product covariate*age +
In this example, we have two covariates in the data file +(fields 2 and 3). The number of covariates is defined with +statement ncov=2. If now you have 3 covariates in the datafile +(fields 2, 3 and 4), you have to set ncov=3. Then you can run the +programme with a new parametrisation taking into account the +third covariate. For example, model=V1+V3 estimates +a model with the first and third covariates. More complicated +models can be used, but it will takes more time to converge. With +a simple model (no covariates), the programme estimates 8 +parameters. Adding covariates increases the number of parameters +: 12 for model=V1, 16 for model=V1+V1*age +and 20 for model=V1+V2+V3.
+or, to simplify:
+or, to simplify (in most of cases it converges but there is no +warranty!):
+12 0.0 0.0 @@ -407,6 +425,45 @@ aij bij 23 0.0 0.0
In order to speed up the convergence you can make a first run with +a large stepm i.e stepm=12 or 24 and then decrease the stepm until +stepm=1 month. If newstepm is the new shorter stepm and stepm can be +expressed as a multiple of newstepm, like newstepm=n stepm, then the +following approximation holds: +
aij(stepm) = aij(n . stepm) - ln(n) +and +
bij(stepm) = bij(n . stepm) .+ +
For example if you already ran for a 6 months interval and
+got:
+
# Parameters +12 -13.390179 0.126133 +13 -7.493460 0.048069 +21 0.575975 -0.041322 +23 -4.748678 0.030626 ++If you now want to get the monthly estimates, you can guess the aij by +substracting ln(6)= 1,7917
12 -15.18193847 0.126133 +13 -9.285219469 0.048069 +21 -1.215784469 -0.041322 +23 -6.540437469 0.030626 ++and get
12 -15.029768 0.124347 +13 -8.472981 0.036599 +21 -1.472527 -0.038394 +23 -6.553602 0.029856 + +which is closer to the results. The approximation is probably useful +only for very small intervals and we don't have enough experience to +know if you will speed up the convergence or not. +-ln(12)= -2.484 + -ln(6/1)=-ln(6)= -1.791 + -ln(3/1)=-ln(3)= -1.0986 +-ln(12/6)=-ln(2)= -0.693 ++Guess values for computing variances
This is an output if mle=1. But it can be @@ -485,14 +542,15 @@ prevalences and health expectancies +102. It is possible to get extrapolated stationary prevalence by +age ranging from agemin to agemax.
-Similarly, it is possible to get extrapolated stationary -prevalence by age ranging from agemin to agemax.
+Setting bage=50 (begin age) and fage=100 (final age), makes +the program computing life expectancy from age 'bage' to age +'fage'. As we use a model, we can interessingly compute life +expectancy on a wider age range than the age range from the data. +But the model can be rather wrong on much larger intervals. +Program is limited to around 120 for upper age!
pop_based=0-
The user has the possibility to choose between -population-based or status-based health expectancies. If -pop_based=0 then status-based health expectancies are computed -and if pop_based=1, the programme computes population-based -health expectancies. Health expectancies are weighted averages of -health expectancies respective of the initial state. For a -status-based index, the weights are the cross-sectional -prevalences observed between two dates, as previously -explained, whereas for a population-based index, the weights -are the stationary prevalences.
+The program computes status-based health expectancies, i.e
+health expectancies which depends on your initial health state.
+If you are healthy your healthy life expectancy (e11) is higher
+than if you were disabled (e21, with e11 > e21).
+To compute a healthy life expectancy independant of the initial
+status we have to weight e11 and e21 according to the probability
+to be in each state at initial age or, with other word, according
+to the proportion of people in each state.
+We prefer computing a 'pure' period healthy life expectancy based
+only on the transtion forces. Then the weights are simply the
+stationnary prevalences or 'implied' prevalences at the initial
+age.
+Some other people would like to use the cross-sectional
+prevalences (the "Sullivan prevalences") observed at
+the initial age during a period of time defined
+just above.
starting-proj-date=1/1/1989 final-proj-date=1/1/1992 mov_average=0
Prevalence and population projections are only available if -the interpolation unit is a month, i.e. stepm=1. The programme -estimates the prevalence in each state at a precise date -expressed in day/month/year. The programme computes one -forecasted prevalence a year from a starting date (1 january of -1989 in this example) to a final date (1 january 1992). The -statement mov_average allows to compute smoothed forecasted -prevalences with a five-age moving average centered at the -mid-age of the five-age period.
+the interpolation unit is a month, i.e. stepm=1 and if there are +no covariate. The programme estimates the prevalence in each +state at a precise date expressed in day/month/year. The +programme computes one forecasted prevalence a year from a +starting date (1 january of 1989 in this example) to a final date +(1 january 1992). The statement mov_average allows to compute +smoothed forecasted prevalences with a five-age moving average +centered at the mid-age of the five-age period.popforecast=0 popfile=pyram.txt popfiledate=1/1/1989 last-popfiledate=1/1/1992
This command is available if the interpolation unit is a -month, i.e. stepm=1 and if popforecast=1. From a data file
- -Structure of the data file pyram.txt -: age numbers
- -+month, i.e. stepm=1 and if popforecast=1. From a data file +including age and number of persons alive at the precise date +popfiledate, you can forecast the number of persons +in each state until date last-popfiledate. In this +example, the popfile pyram.txt +includes real data which are the Japanese population in 1989. + +
For example 70 10.9226 3.0401 5.6488 6.2122 means: -e11=10.9226 e12=3.0401 e21=5.6488 e22=6.2122+
For example 70 10.4227 3.0402 5.6488 5.7123 means: +e11=10.4227 e12=3.0402 e21=5.6488 e22=5.7123
For example, life expectancy of a healthy individual at age 70
-is 10.92 in the healthy state and 3.04 in the disability state
-(=13.96 years). If he was disable at age 70, his life expectancy
-will be shorter, 5.64 in the healthy state and 6.21 in the
-disability state (=11.85 years). The total life expectancy is a
-weighted mean of both, 13.96 and 11.85; weight is the proportion
+is 10.42 in the healthy state and 3.04 in the disability state
+(=13.46 years). If he was disable at age 70, his life expectancy
+will be shorter, 5.64 in the healthy state and 5.71 in the
+disability state (=11.35 years). The total life expectancy is a
+weighted mean of both, 13.46 and 11.35; weight is the proportion
of people disabled at age 70. In order to get a pure period index
(i.e. based only on incidences) we use the computed or
@@ -813,14 +904,14 @@ href="trbiaspar.txt">-Total life expectancy by
@@ -921,16 +1012,30 @@ program while saving the old output file
On a d'abord estimé la date moyenne des interviaew. ie
-13/9/1995. This file contains Example, at date 1/1/1989 : 73 0.807 0.078 0.115 This means that at age 73, the probability for a person age 70
-at 13/9/1989 to be in state 1 is 0.807, in state 2 is 0.078 and
-to die is 0.115 at 1/1/1989. First,
+we have estimated the observed prevalence between 1/1/1984 and
+1/6/1988. The mean date of interview (weighed average of the
+interviews performed between1/1/1984 and 1/6/1988) is estimated
+to be 13/9/1985, as written on the top on the file. Then we
+forecast the probability to be in each state. Example,
+at date 1/1/1989 : Since
+the minimum age is 70 on the 13/9/1985, the youngest forecasted
+age is 73. This means that at age a person aged 70 at 13/9/1989
+has a probability to enter state1 of 0.807 at age 73 on 1/1/1989.
+Similarly, the probability to be in state 2 is 0.078 and the
+probability to die is 0.115. Then, on the 1/1/1989, the
+prevalence of disability at age 73 is estimated to be 0.088.- Prevalence forecasting:
frbiaspar.txt
-# StartingAge FinalAge P.1 P.2 P.3
+# Forecasting at date 1/1/1989
+ 73 0.807 0.078 0.115
+
+- Population forecasting:
poprbiaspar.txt
@@ -946,9 +1051,14 @@ to die is 0.115 at 1/1/1989.
From the population file, we estimate the number of people in +each state. At age 73, 645857 persons are in state 1 and 69320 +are in state 2. One year latter, 512892 are still in state 1, +85003 are in state 2 and 117282 died before 1/1/1990.
+Since you know how to run the program, it is time to test it on your own computer. Try for example on a parameter file named Enter the parameter fi
IMACH, Version 0.7 Enter
+ Enter
the parameter file name: ..\mytry\imachpar.txt |