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 <title>Computing Health Expectancies using IMaCh</title>  <title>Computing Health Expectancies using IMaCh</title>
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Line 320  line</font></a></h4> Line 327  line</font></a></h4>
             <li>... </li>              <li>... </li>
         </ul>          </ul>
     </li>      </li>
     <li><b>ncov=2</b> Number of covariates in the datafile. The      <li><b>ncov=2</b> Number of covariates in the datafile. </li>
         intercept and the age parameter are counting for 2  
         covariates.</li>  
     <li><b>nlstate=2</b> Number of non-absorbing (alive) states.      <li><b>nlstate=2</b> Number of non-absorbing (alive) states.
         Here we have two alive states: disability-free is coded 1          Here we have two alive states: disability-free is coded 1
         and disability is coded 2. </li>          and disability is coded 2. </li>
Line 348  line</font></a></h4> Line 353  line</font></a></h4>
 <h4><font color="#FF0000">Covariates</font></h4>  <h4><font color="#FF0000">Covariates</font></h4>
   
 <p>Intercept and age are systematically included in the model.  <p>Intercept and age are systematically included in the model.
 Additional covariates (actually two) can be included with the command: </p>  Additional covariates can be included with the command: </p>
   
 <pre>model=<em>list of covariates</em></pre>  <pre>model=<em>list of covariates</em></pre>
   
Line 368  Additional covariates (actually two) can Line 373  Additional covariates (actually two) can
         the product covariate*age</li>          the product covariate*age</li>
 </ul>  </ul>
   
   <p>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, <strong>model=V1+V3 </strong>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 <strong>model=V1, </strong>16 for <strong>model=V1+V1*age
   </strong>and 20 for <strong>model=V1+V2+V3.</strong></p>
   
 <h4><font color="#FF0000">Guess values for optimization</font><font  <h4><font color="#FF0000">Guess values for optimization</font><font
 color="#00006A"> </font></h4>  color="#00006A"> </font></h4>
   
Line 397  aij bij</b> </p> Line 415  aij bij</b> </p>
 23  -6.234642  0.022315 </pre>  23  -6.234642  0.022315 </pre>
 </blockquote>  </blockquote>
   
 <p>or, to simplify (in most of cases it converges but there is no warranty!): </p>  <p>or, to simplify (in most of cases it converges but there is no
   warranty!): </p>
   
 <blockquote>  <blockquote>
     <pre>12 0.0 0.0      <pre>12 0.0 0.0
Line 484  prevalences and health expectancies</fon Line 503  prevalences and health expectancies</fon
 to calculated stationary prevalence, transitions probabilities  to calculated stationary prevalence, transitions probabilities
 and life expectancies at any age. Choice of age range is useful  and life expectancies at any age. Choice of age range is useful
 for extrapolation. In our data file, ages varies from age 70 to  for extrapolation. In our data file, ages varies from age 70 to
 102. It is possible to get extrapolated stationary  102. It is possible to get extrapolated stationary prevalence by
 prevalence by age ranging from agemin to agemax. </p>  age ranging from agemin to agemax. </p>
   
   <p>Setting bage=50 (begin age) and fage=100 (final age), makes
 <p>Setting bage=50 (begin age) and fage=100 (final age), makes the program computing  the program computing life expectancy from age 'bage' to age
 life expectancy from age 'bage' to age 'fage'. As we use a model, we  'fage'. As we use a model, we can interessingly compute life
 can interessingly compute life expectancy on a wider age range than the age  expectancy on a wider age range than the age range from the data.
 range from the data. But the model can be rather wrong on much larger  But the model can be rather wrong on much larger intervals.
 intervals. Program is limited to around 120 for upper age!</p>  Program is limited to around 120 for upper age!</p>
   
 <ul>  <ul>
     <li><b>agemin=</b> Minimum age for calculation of the      <li><b>agemin=</b> Minimum age for calculation of the
Line 527  expectancies</font></h4> Line 546  expectancies</font></h4>
   
 <pre>pop_based=0</pre>  <pre>pop_based=0</pre>
   
 <p>The program computes status-based health expectancies, i.e health  <p>The program computes status-based health expectancies, i.e
 expectancies which depends on your initial health state.  If you are  health expectancies which depends on your initial health state.
 healthy your healthy life expectancy (e11) is higher than if you were  If you are healthy your healthy life expectancy (e11) is higher
 disabled (e21, with e11 &gt; e21).<br>  than if you were disabled (e21, with e11 &gt; e21).<br>
 To compute a healthy life expectancy independant of the initial status  To compute a healthy life expectancy independant of the initial
 we have to weight e11 and e21 according to the probability to be in  status we have to weight e11 and e21 according to the probability
 each state at initial age or, with other word, according to the  to be in each state at initial age or, with other word, according
 proportion of people in each state.<br>  to the proportion of people in each state.<br>
   We prefer computing a 'pure' period healthy life expectancy based
 We prefer computing a 'pure' period healthy life expectancy based only  only on the transtion forces. Then the weights are simply the
 on the transtion forces. Then the weights are simply the stationnary  stationnary prevalences or 'implied' prevalences at the initial
 prevalences or 'implied' prevalences at the initial age.<br>  age.<br>
   Some other people would like to use the cross-sectional
 Some other people would like to use the cross-sectional prevalences  prevalences (the &quot;Sullivan prevalences&quot;) observed at
 (the "Sullivan prevalences") observed at the initial age during a  the initial age during a period of time <a href="#Computing">defined
 period of time <a href="#Computing">defined just above</a>.  just above</a>. </p>
   
 <ul>  <ul>
     <li><strong>popbased= 0 </strong> Health expectancies are computed      <li><strong>popbased= 0 </strong>Health expectancies are
     at each age from stationary prevalences 'expected' at this initial age.</li>          computed at each age from stationary prevalences
     <li><strong>popbased= 1 </strong> Health expectancies are computed          'expected' at this initial age.</li>
     at each age from cross-sectional 'observed' prevalence at this      <li><strong>popbased= 1 </strong>Health expectancies are
     initial age. As all the population is not observed at the same exact date we          computed at each age from cross-sectional 'observed'
     define a short period were the observed prevalence is computed.</li>          prevalence at this initial age. As all the population is
           not observed at the same exact date we define a short
           period were the observed prevalence is computed.</li>
 </ul>  </ul>
   
 </p>  
   
 <h4><font color="#FF0000">Prevalence forecasting ( Experimental)</font></h4>  <h4><font color="#FF0000">Prevalence forecasting ( Experimental)</font></h4>
   
 <pre>starting-proj-date=1/1/1989 final-proj-date=1/1/1992 mov_average=0 </pre>  <pre>starting-proj-date=1/1/1989 final-proj-date=1/1/1992 mov_average=0 </pre>
   
 <p>Prevalence and population projections are only available if the  <p>Prevalence and population projections are only available if
 interpolation unit is a month, i.e. stepm=1 and if there are no  the interpolation unit is a month, i.e. stepm=1 and if there are
 covariate. The programme estimates the prevalence in each state at a  no covariate. The programme estimates the prevalence in each
 precise date expressed in day/month/year. The programme computes one  state at a precise date expressed in day/month/year. The
 forecasted prevalence a year from a starting date (1 january of 1989  programme computes one forecasted prevalence a year from a
 in this example) to a final date (1 january 1992). The statement  starting date (1 january of 1989 in this example) to a final date
 mov_average allows to compute smoothed forecasted prevalences with a  (1 january 1992). The statement mov_average allows to compute
 five-age moving average centered at the mid-age of the five-age  smoothed forecasted prevalences with a five-age moving average
 period. </p>  centered at the mid-age of the five-age period. </p>
   
 <ul>  <ul>
     <li><strong>starting-proj-date</strong>= starting date      <li><strong>starting-proj-date</strong>= starting date
Line 1000  are in state 2. One year latter, 512892 Line 1019  are in state 2. One year latter, 512892
   
 <hr>  <hr>
   
 <h2><a name="example"> </a><font color="#00006A">Trying an example</font></a></h2>  <h2><a name="example"></a><font color="#00006A">Trying an example</font></h2>
   
 <p>Since you know how to run the program, it is time to test it  <p>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 <a  on your own computer. Try for example on a parameter file named <a
Line 1191  href="mailto:brouard@ined.fr">mailto:bro Line 1210  href="mailto:brouard@ined.fr">mailto:bro
 href="mailto:lievre@ined.fr">mailto:lievre@ined.fr</a> .</p>  href="mailto:lievre@ined.fr">mailto:lievre@ined.fr</a> .</p>
   
 <p>Latest version (0.71a of March 2002) can be accessed at <a  <p>Latest version (0.71a of March 2002) can be accessed at <a
 href="http://euroeves.ined.fr/imach">http://euroreves.ined.fr/imach</a><br>  href="http://euroreves.ined.fr/imach">http://euroreves.ined.fr/imach</a><br>
 </p>  </p>
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