<?xml version="1.0" encoding="utf-8"?>
<ManualTopic ID="/baanerp/cp/onlinemanual/000112" xml:lang="en">
   <Header>
      <Title>Forecast method: time-series analysis</Title>
      <Keyword type="header" order="d1e203581">
         <Level1>Forecasting method: time-series analysis</Level1>
      </Keyword>
      <Keyword type="header" order="d1e203584">
         <Level1>Time-series analysis</Level1>
      </Keyword>
   </Header>
   <GeneralSection>
      <Paragraph>ERP Enterprise calculates the
      demand forecast according to the <GUIRef href="/baanerp/cp/domains/rpd.fcmd#tsa" role="option">Time Series Analysis</GUIRef> forecast method based on the average demand and any earlier
      defined trend influence and seasonal influence.</Paragraph>
      <Paragraph>The demand forecast is
      computed as follows:</Paragraph>
      <Paragraph>Without trend influence:</Paragraph>
      <Formula space-and-orientation="indented-estimated">
         <Paragraph>TD(t) = AV</Paragraph>
      </Formula>
      <Paragraph>With a linear trend influence:</Paragraph>
      <Formula space-and-orientation="indented-estimated">
         <Paragraph>TD(t) = CS + TF * t</Paragraph>
      </Formula>
      <Paragraph>With a progressive trend influence:</Paragraph>
      <Formula space-and-orientation="indented-estimated">
         <Paragraph>TD(t) = BS * TF ^ (t-1)</Paragraph>
      </Formula>
      <Paragraph>With a constant seasonal influence:</Paragraph>
      <Formula space-and-orientation="indented-estimated">
         <Paragraph>FD(t) = TD(t) + SF(t)</Paragraph>
      </Formula>
      <Paragraph>With a progressive seasonal influence:</Paragraph>
      <Formula space-and-orientation="indented-estimated">
         <Paragraph>FD(t) = TD(t) * SF(t)</Paragraph>
      </Formula>
      <Paragraph>Where:</Paragraph>
      <TABLE border="1" borderstyle="default" space-and-orientation="indented-estimated">
         <TBODY noTR="7">
            <TR no="1" isLast="false">
               <TD width="16" rowspan="1" colspan="1">AV</TD>
               <TD width="305" rowspan="1" colspan="1">average
            demand (*)</TD>
            </TR>
            <TR no="2" isLast="false">
               <TD width="16" rowspan="1" colspan="1">CS</TD>
               <TD width="305" rowspan="1" colspan="1">constant
            demand</TD>
            </TR>
            <TR no="3" isLast="false">
               <TD width="16" rowspan="1" colspan="1">BS</TD>
               <TD width="305" rowspan="1" colspan="1">base demand (the
            estimated demand for period 1)</TD>
            </TR>
            <TR no="4" isLast="false">
               <TD width="16" rowspan="1" colspan="1">TF</TD>
               <TD width="305" rowspan="1" colspan="1">trend factor</TD>
            </TR>
            <TR no="5" isLast="false">
               <TD width="16" rowspan="1" colspan="1">SF(t)</TD>
               <TD width="305" rowspan="1" colspan="1">seasonal factor for period t</TD>
            </TR>
            <TR no="6" isLast="false">
               <TD width="16" rowspan="1" colspan="1">TD(t)</TD>
               <TD width="305" rowspan="1" colspan="1">trend based demand for period
            t</TD>
            </TR>
            <TR no="7" isLast="true">
               <TD width="16" rowspan="1" colspan="1">FD(t)</TD>
               <TD width="305" rowspan="1" colspan="1">demand forecast for
            period t</TD>
            </TR>
         </TBODY>
      </TABLE>
      <Paragraph>(*) The average demand
      is the sum of the historical demand figures by period, divided by the number of
      periods with demand history.</Paragraph>
   </GeneralSection>
   <RelatedTopics>
      <SectionTitle>Related topics</SectionTitle>
      <RelTopic>
         <Link href="/baanerp/cp/onlinemanual/000079" role="manual">Algorithm for demand forecasting</Link>
      </RelTopic>
      <RelTopic>
         <Link href="/baanerp/cp/onlinemanual/000321" role="manual">Forecasting methods</Link>
      </RelTopic>
   </RelatedTopics>
</ManualTopic>