--- imach096d/doc/imach.htm 2002/03/06 18:56:09 1.6 +++ imach096d/doc/imach.htm 2002/03/11 15:24:05 1.9 @@ -1,3 +1,4 @@ + @@ -6,6 +7,13 @@ content="text/html; charset=iso-8859-1"> Computing Health Expectancies using IMaCh + + + + + + @@ -29,7 +37,7 @@ color="#00006A">INEDEUROREVES

Version -0.7, February 2002

+0.71a, March 2002


@@ -58,8 +66,6 @@ color="#00006A">) -
  • ncov=2 Number of covariates in the datafile. The - intercept and the age parameter are counting for 2 - covariates.
  • +
  • ncov=2 Number of covariates in the datafile.
  • nlstate=2 Number of non-absorbing (alive) states. Here we have two alive states: disability-free is coded 1 and disability is coded 2.
  • @@ -349,7 +353,7 @@ line

    Covariates

    Intercept 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.

    +

    Guess values for optimization

    @@ -398,7 +415,8 @@ aij bij

    23 -6.234642 0.022315 -

    or, to simplify:

    +

    or, to simplify (in most of cases it converges but there is no +warranty!):

    12 0.0 0.0
    @@ -407,6 +425,14 @@ 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(n stepm) = aij(stepm) +ln(n)
    +
    and +
    bij(n stepm) = bij(stepm) .

    Guess values for computing variances

    This is an output if mle=1. But it can be @@ -485,14 +511,15 @@ 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!