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    <title>topic How to calculate the p-trend of age-adjusted incidences in Statistical Procedures</title>
    <link>https://communities.sas.com/t5/Statistical-Procedures/How-to-calculate-the-p-trend-of-age-adjusted-incidences/m-p/709551#M34360</link>
    <description>&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;I need to calculate the p-trend of age-adjusted incidences. The age-adjusted incidences were calculated using the direct method, so&amp;nbsp;the numerators and denominators were large. I tried the poison model and found the p-trend was &amp;lt;0.0001, but the incidence rates seem to be non-linear, rather than an increased or decreased trend.&amp;nbsp; Also, I found the value/df are very high (&amp;gt;3500), which should be close to 1 for better accuracy. Is it right to use poison model? Which model is good for calculating the&amp;nbsp;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;&amp;nbsp;p-trend of age-adjusted incidences?&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;data a;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;input periods cases pyears;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;loga=log(pyears);&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;datalines;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;1 10000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;2 25000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;3 20000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;4 15000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;run;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;proc genmod data=a;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;model cases=periods / dist=poisson link=log offset=loga;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;run;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;</description>
    <pubDate>Wed, 06 Jan 2021 04:26:10 GMT</pubDate>
    <dc:creator>lijiaqi</dc:creator>
    <dc:date>2021-01-06T04:26:10Z</dc:date>
    <item>
      <title>How to calculate the p-trend of age-adjusted incidences</title>
      <link>https://communities.sas.com/t5/Statistical-Procedures/How-to-calculate-the-p-trend-of-age-adjusted-incidences/m-p/709551#M34360</link>
      <description>&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;I need to calculate the p-trend of age-adjusted incidences. The age-adjusted incidences were calculated using the direct method, so&amp;nbsp;the numerators and denominators were large. I tried the poison model and found the p-trend was &amp;lt;0.0001, but the incidence rates seem to be non-linear, rather than an increased or decreased trend.&amp;nbsp; Also, I found the value/df are very high (&amp;gt;3500), which should be close to 1 for better accuracy. Is it right to use poison model? Which model is good for calculating the&amp;nbsp;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;&amp;nbsp;p-trend of age-adjusted incidences?&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;data a;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;input periods cases pyears;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;loga=log(pyears);&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;datalines;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;&amp;nbsp;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;1 10000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;2 25000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;3 20000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;4 15000 50000000&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;run;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;proc genmod data=a;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;model cases=periods / dist=poisson link=log offset=loga;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;&lt;DIV class=""&gt;&lt;DIV class="public-DraftStyleDefault-block public-DraftStyleDefault-ltr"&gt;&lt;SPAN&gt;run;&lt;/SPAN&gt;&lt;/DIV&gt;&lt;/DIV&gt;</description>
      <pubDate>Wed, 06 Jan 2021 04:26:10 GMT</pubDate>
      <guid>https://communities.sas.com/t5/Statistical-Procedures/How-to-calculate-the-p-trend-of-age-adjusted-incidences/m-p/709551#M34360</guid>
      <dc:creator>lijiaqi</dc:creator>
      <dc:date>2021-01-06T04:26:10Z</dc:date>
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