"A stock takes time to change, because flow takes time to flo..." — Donella H. Meadows

Quote
Catalog

A stock takes time to change, because flow takes time to flow.

— Donella H. Meadows

Thinking in Systems: A Primer

Systems Thinking in Systems: A Primer Time

More from Donella H. Meadows

View all quotes

Quote
Catalog

The time lags imposed by stocks allow room to maneuver, to experiment, and to revise…

Quote
Catalog

The elements, the parts of systems we are most likely to notice, are often (not always)…

Quote
Catalog

A system generally goes on being itself, changing only slowly if at all, even with…

Quote
Catalog

Changing [a system's] elements usually has the least effect on the system.




                                                                                             &&MK KK  K
                                                                                            MWWWWWWWWWWWWWWK&W
                                                                                           MWWWWMMWWWWWWWWWWWWWMK
                                                                                           WWKKWWWWMK&MWWWWWWWWMWMM
                                                                                          WW &WWWWWWWWMMWWWWWWWMWWM&&
                                                                                          W&K&WWWWWWWWMMWWWWWWWWWWMMMK
                                                                                          WWWMWM&&K&WWWWWWWWWWWWWWWM&     KK
                                                                                         MWW       WWWWWWWWWWWWWWMWM&KK MM  WWWWWM
                                                                                         WWWWW   MWWWWWWWWWWWWMMMMM&  KMW MW   MWWW
                                                                                       KWWWWWWMWWWWWWWWWWWWWWMMM&&&&  K WWWW  WWWWWM
                                                                                     KWWWWWWWWWWWWWWWWWWWWWM&&&&&&M&KMWWWWW&MWWWWKWW
                                                                                   KWWWWWWWWWWWWWWWWWWM&&&KK   &MM&&KWWWW  KWWWW& WW
                                                                                 WWWWWWWWWWWWWWWWWWWWM&KKKK  KK&MMWMMWWWKWW W WW KW
                                                                                 WWWWWWWWWWWWWWWWWWWM&MMMMM&K&K&MMWWWWWWWWW MMW  M
                                                                                 &M    &&WWWWWWWWWWWMMMMMWM&&K&MMMM&MWWWWWW&&WWW
                                                                                    KWWWWWWWWWWWWWWWMMWWMM&&KK&&MM&&&&KKWWWWWWM
                                                                                     WWWWWWWWWWWWWWMMWWWWMM&&&&&&&KKKK WWWWWK
                                                              MM                    WWWWWWWWWWWWWWWWWWWWWWM&&&KKKK     KM&
                                                        &W   WWM                   &&  KK KWWWWWWWWWWWWWWWM&&&K
                                                      WWWW  &WK                      MW     &WWWWWWWWWWWWWM&&KK         WWK                      M           K&&K
                                                      WW                             &     KWWWWWWWWWWWWWWM&&KK        &WWMK                    MK MM MMM&KMK&K&
                                                                                          WWWWWWWWWWWWWWWMM&KKK        &WWMK          K   KWWWWWWWWWWMKKK  MK     KK
                                                                  &WK                  KWWWWWWWWWWWWWWWWMM&&KK        KWWWW&        MK   &WWMWWWKK&  &MK K K K KKK
                                                                 WW&                  MWWWWWWWWWWWWWWWWM&&K          KMWWWW&K     &     &&KKWWMWW  &&M      MMM     K
                                                                 WW                    WWWWWWWWWWWWWWM&&K            &WWWWW&&K   KM   &&&&    &WWW&   &       WK&
                                                                 WWK                   WWWWWWWWWWMM&KK              &WWWWWM& &K KWMMK  K         WWMM          &K  &&K K
                                                                 WWW&                 &WWWWWWM&&KK                K&WWWWWWWMWM K&W K &&&K   K K    &WM          KK  K
                     W                                            WW&                KWWWWWMMK                  K&MMWWWWWWWW&&M&K&KMWK                  K        &
                                                      KWWWM      WWM                 MWMM&                   KK&MMWWWWWWW&&&WMKKK KWWK             K&        &&M        K
                                             KWW   WWWWW         WWWM                                   KMMMMMWWWWWWWWWW&KKMKKKKK WWK&               W&       MMK
                                            WWWW   &            MWWWM       K                          &MWWWWWWWWWWWWWW&KKK&K    &WMK&   W           KM KM&KK KMMW&
                                           WWW                 MWWWWK                                   &WWWWWWWWWWWW&&KK&K   K&K M&M&  K&        K&W& M&MWWWWWWWMWW
                                          WWWW                   WWW                                       WWWWWWWWW&KKKK     &   MWK   W        &WWMWWWMWWWWWWWWW&&M

,.,,,..,,,.,,,,:::,:    :,:,:: :     :                ::::                                 .,. ,:      .,, :,     ,                ,:     . ,  ..     .   ,                    ::,,.
.,,,,,,,.,,,,,:,:::      ::::::      ::             :    :                                                  : .     ,.                .. ,,    .:  ..                         : :,:,
,,,,:,,,,.,,:,::,,::: : ,:,,:: :     ::                                                     ::     :,: ,,.  ., .:      ,            .         . ,.  .                           ::,.
,,,,,,,,,,,,,,:::: :   : ,: ,: :                                                  :       ,:,            :      :   :::.       ,         , :    .          .                    : ,:
,,:,::,.,,,:,::,::  :   ::,,::      :::                                                    ,                   .,     .        ,  .   :.                                          ::
,,::::::,,,,,:,,::: :: :::.         :                                          :                                        :      :,  , ..             ,       ,                      :
::::::,,,::,::::::     :::,,,      : :                                                                                 ,:: ,::  ::   ...     .     .                               :
,:::::,:,,,:,,:::::  :  ::,:,::     :                                                    :                              : ,     :                            ,
:::::::::,,,,::::::::: :::,::                                                                                                   ,
:::::::::,:::,::, : : ::,,::::      :                                                                                          ,
::: ::::,:,:,:,,,::: : : :,                                                             :                                            ,.
::: :::,:,,,,,:::   :   :::                                                                                                   .       :. ..
::: :::,:,.,,,,:::  :   ::                                                                                                  :         .. .                      :
: ::::,,,,,,,,:, :    ::                                                                                                             ,
:::::,,,,,,,,,,,::: :    ::                                                                                                               .                      ,
,::::::,,,,,,,,:,    :: : :
::::::,,,:,,,,,::::: :      :                                                                                                        .
, :, :,,,:,,,: ::::       :                                                                                                          .,
:::::::,,,,,:,:,::: :: : :                                                                                                           ,
: ::::,:,,,,,,:::  :    : :                                                                                                        ,,.,
   :: :::,,,,::::::    : :                                                                                                 ,                        :
:     ::::::,::::   :   :                                              :,    :                                           .          .
: :  :::::::::: : ::                                           , , ,                    :,                                 :                   .            :
        ::: , : ::                                                .                       ,                                  ,     :    ::,
 :    :  :: :                                      : :                                 .                           ::               ,
  :    :::  :                               .                             ,                                      :..,            ,
:        :  ,                      ,..                               ,                                           ::                    :               .  ,
:     : : ::              :,..                                                                                ,:, .             .                           .
         :  :      :..                                                                                    :,,,.                               :.        .  .::
:                    .                                                ,     :                         :......  ,                             : . .:      :    ::
         ,..        .                                                 :                            :.,,., .                                      ,,             :
     .                                                      :.        ,                       .   .,, .  :                              ,    .           .           .
                                       ..   :   . .             .                        ::    ... .                                       . :,.  .     .  .      :
     .                        .,,                .    , .     ,                        , .        . , .                                   ,:...., .                .,  : ,
               .,,:  ,..                       ,:.  .,:              .                   . ,  ,                                        .  .,,.. ,                    ,
                                               . .: ::        .                                  : :                       ,    :           ..,                          ,

                    ~~~~      ~ ~~<~~ ~~~~<<<<<~<~~~~~    ~~~~~<<~<<~<*****<*<~<<<<<<****~<      <~}~**   }        *                         <<     *~           }}*<<<<<~~~~~~
                   ~~~~~~      ~~~~~~  ~~~<~<<<<<~<< ~<~~ ~~<~<*~*<**<<<<****<<<~<~<<}***<}<<~*<**~~<<*<~*<}     ~                 *<      ~ *}            }     }}*<<<*~<<<~~ ~
                     ~ ~      ~ ~<~~~  ~~~<<<<*<<~<<<~~~~~~<~<<*<<*<*<<}*<**<~<~~~~~<***<* }   << *   *   <<  ~    * *~            ~ <<  }** *             <     }}**<*<<<<<~~~~
                  ~ ~~~ ~  ~  ~ ~~~~~~~~~<<<<<<<<<<~~<<<~<~<<***<*<***<****<*<<~~~ <<***<*              }   }  ~ *}}               ~~* ~  ~ <~                    }}****<**<~<~~ ~
                  ~~ ~~~      ~~~~~~   ~~~*<*<<<<<<<<<<<<<<<<*<*}**}**}****}<<<~~~~<**<***                       ~ } <             <**     < ~                     }***<<*<*<<<<~~
                   ~  ~    ~~~~~~~<~ ~~~~<<****<<<<<<**<<<****}*}*}*}}}}*****<< ~<<~*****}                        }   ~       ~  ~* *                              }********<*<<<~~
                  ~~~~~      ~~~<~~ ~ ~~~<*<**<<<*<<<**~<<****}}*}}}}}}******<<~~<<*****<~                           }~   <    }                                   }****}*}****<<<~
                   ~~ ~~       ~~~~~ ~~~~<*******<***<*<***}}}} }} }  }}}}}**<~~<~<<**}**                              <   <}  <                                  } **}** }}}***<<~~
                      ~      ~~~<~~~~~~~~<***<**********}**}*} *}}    }}}} }**<<~~**}*}}<}                             }}<~    <                              }    }}}*}}*  *}<**<~<
                 ~ ~ ~        ~<<<<~ <~<<**}}*<<***}}}***}}}}}   } }    }}}}*}<*<*<*}}}}~                                   *                                       }}}    }} }**<<~
   ~                ~ ~ ~  ~~<~~<<<~~~~<<**}*}}}*}}*}}*}}}*}    }        } }}***<<**}} }                                                                       ~   }}}} }    }}**}<~
   ~             ~~~ ~~~   ~~~~<*<~~<<<<<*}*}}}}}**}}*}*} }}            }} }}}}<*}}} }}~       }                                   ~ <                          }            }}* <<~
   ~              ~~ ~~~  ~~~~~~<<*<<<<**}}  }}*}}}*}}}*}}  }                }}*}*}}}<~                                              *                               }         }***<
 ~              ~ ~<~~  ~~~~~~<<~*<<<<*<*}} }  }*}}}}}}}}}*  }               }}****<~                                                 ~                          <             }}}<<
                   ~ ~<<~  ~~~*****<*<**}} }  }}}}}}}}}**                }   }}}*~                                                    <                                        }}}*<
                 ~~~~  ~ ~ <<<<<*<******}     }*}* }}}}}*}} }                 }}<                                               ~                                                }*<
                    ~ ~~~~~~ <<*}<*<**}}}   } } }    }}*}}  }               }}}<                                                      ~                                     }    }*<
 ~  ~         ~    ~~~~~~~ ~~*<**<****}}*       }}  }*}}}}                     *<  }                                                                                             *<<
                   ~  ~ ~ ~~<<*<**}****} }     } }} }}}}                       }*<                                             ~      ~                          }               }}<
 ~               ~~ ~~~~ ~ ~~<<<*<****}}     }  * }  } }}}}   }               }  }}}                                         ~                                  *                }**
~~~  ~             ~~~~ ~ ~<<<**}****}}}}       }}} } }}**} }*                  } }                                                 ~                          *                  }<
 ~~~~~           ~~~ ~~~ ~~~<<**}*}***}}       }}*   *~<        }}   **       *   }                                                ~                          *                   }<
 ~ ~<          ~ ~  ~~~~~~<<<<<**}****}}}     }}}}  }<    *<      ~    ~        }                                   }}             ~        *~          ~                         **
~~~~~~~~   ~ ~ ~  ~<~<<~~~<<<<*****<***}}     }}}                       }             }~}<                         }<*            ~   ~     <        *                            }*
~ ~<~~ ~~  ~ ~~~~<<<<<~<<~<<<*<<***<*}*}}        *<     <                             < <                        }~  *       }<~  ~  ~ *~                *                        }*
~~ <~~~   ~~ ~<~<<<<<<<<~<<<<<*****}*}   }<~                                                                                 }                      }                              *
 ~~~<~~~~ ~~ ~<<~<<<**<<*<<**}* }*<                                                                            }~   <                            <    *    ~                      }*
 ~~<<~ ~ ~  ~<<<<<*<***}**                                          }<           }   ~                      }~                 ~            *      <}                              *
<~~<<~~~~ <~ ~<*<*<                                                                  }                  }*         *                       <    <             ~                    }
 <~<<<~~~~<<<}*<** <<                                                                                <          *                                          }<*    ~               **
<<<<~<<<~          ~                                     *             ~<                        }~        <}                          *  ** < ~~  ~ ~       <          }         }*
<<<<                 *                                               ~                      }~       ~                                   < }~ <<~ }       ~<        * *<         }}*
<<<< }                                   ~<<             *<~         ~~                 *  <           <                                ~   ~          <     <          }         }*
<*<*<                            ~**}      }         < *             ~*                      }       ~                                                                           }}*
<<<<<*~            *<   ~~<} }    }}                         ~                          < ~ *                                                    *                  }     ~       }<
<<**<<<*<<****}*}*****}}<******}}}}}}         }    ~           <<                          *   *  <   **                       *      <<  ~    ~                       ** *       **

                                                                                                             j                                     o       VjjVoj
                                                                                                             j    jj                        U               joooo
                                                                                          j   j  j               jj j                  Uj   j               ooooo
                                                                                                 V  Vo o   V                          o                     oooooo
                                                                                                              j   j o                                       joVVojj
                                                                                                                 V oVV                                       oVVojj
                                                                                          o                        Uo         o                              oVVojj
                                                               j  j jj                      U                        Uo  j   oo                               VVoo j     j
                                                              j   jjjj    j                                           V    VUoj                                oooj       jj
                                                              jjj j ojjj                 V                           UVjjV                                     VVojj   jjjj  j
                                                            jjjj jojjjjjj j           j     V     o                    V  UU                                    oVo    j jjjj
                                                         j  jjjjjjjojjjj  j         j   j     o o                   UU   o  V                                    oVjjjjjjjjoj   j
                                           jj             jj jjjjjojjjjjjjjjj                                       Uo U     U                                   jooj jojjjjjjj
                                           j jj            jj jjjjojjjjjjjjjj                                                                                     ojoojojooojjj
                                          j jj           jjjjjjjjooojoojj jjj     j                         UUU          oo      V                                oVoojojojoojj
                                         jjojj    j        j jjjoojojojjjjjjjj                             UU              U U     V  j                           ooojooooooojojj
                                         joo j j jojj     jj jjojoooooooojjj    U                                          U   VU                                 VVVooVoooo ojjj
                                         jooojjj  jj      jjjjojooooooojjjjjjjj       o                                         o                                 VVVoVVooooojojj
                                        j ojooj j  j    jjjjjoooooooVjooooojjjj   oV                                                                              VVVVVVVoooojjjj
                                        joojo jj j jj j    jjj jjooooooooooojj jj   j                                 U                                          VVVVoVVVVVooojoj
                                         joooojj   j j     j    oooVVVVoVVVVVojj j U                              UUVVj   o                                     UUUVVVVVVVoooooojj
                                        oooojjj   jjj     Ujj     Voj          ojj   jU  U                     UUUUVojjoU                                      UUUUUVUVVVVVooooojj
                                         oojoj    jj                             jjUj  j                       UVVVj  oU                        U      U U       UUUVVUVVVVVoooojj
                                         oojjj   jojjV  V                        jojj                          UVVj   o     V          U      oU  j             UUUVUUUVVVVooVoojj
                                         joooVVoo     jj       oU                 oooo   V                     Uo     V     V                             U  VUVjU  UUUUUVoVVVoojj
                                      joo                                         VoooV                       UVj    o      U VU   o               V    U V U V   UUUUUUVVVVoVooojj
                               j                                    V             VooV                     UUUo              UVj   Vj U           V            VUVUU UUUUUVVVVVooj
                                                                   V              ooo U                  UVj        o         V    UUo    VU j       j U     V   VjUUVUUUUVVoVooojj
                                                                    Vj          joooV V               Uo                    U  U     jV UVj UV                   jU   V UVoVoVooojj
                  U                                                  j       joooooooo            Uoj            V            U   U U    Ujj    V         U        V ojVUUUVoVoojj
                 UV   U                                   o      U   V   VUVVoooooooo         Voj            oVV                      V jV  j U       Vj UUUV U   oVoVUV oVVoVoooj
    j                                                      V        U  UUUVVooojjooVo     Uo              VUU                    U    oo  o      j   oj     o   o U      UoVooooj
                                                        U              UUUVooooooooVVVUo                                         U    Uo UV     Uo               V  o    oUUVVVojj
                                     oVUVVo     U V V          V       UVooU UVVVUUooVo                                      UUUU     VoV          VV  U     U            jVVoooj
                            j jjjj  jjoooVV   U               V       VUUVVVoooVUUUUUUVo     j        oV                   UUV   U    V               V                    joVoojj
                                     jjoVj                          j VUUVVVooUUUUUUUUVUVoo VoV o       jUV              Vo  U   V   V   j      o                    VV    jVVVooj


                                     MWM&K
                                    MWWWWWWWW&
                                    WWWWWWWWWWW
                                    W  MWWWWWWK MW W
                                  WWWWWWWWW&&MKWW&WWW
                                WWWWWWWWM&&K&WWWWMW
                                  WWWWWWWWM&MM&MWWK
                      K W&       &WWWWWWWWW&K
                     &W              WWWWWW&K   W        &K &  K
                          W        WWWWWWWMK   WW&     MWW K   K
                          W        WWWWMK      WWMKK& K   &
                      K   W       WWK       &WWWWM& M
                 MW       W              &WWWWWW&KKKW          WM
                 W                        &WWWM     M     KWWWWWWW
                 W&    WWW            K    WW&      W     WWWWWWWWK
                 MWK WWWW&        K &  K   KK     K MMK  WWMM& MK
                  WWWWWW&        KW&M&&&&K &    K   & M&MWWWWM
                  WWM&WW         KWM&&        M&   & KK&MWWWW&
                  WWWWWK     KKMMWWWMWM   K      K&       K&W&
                  WWMMK    M&&WMMW& WWM   &K  K         M    &
                  WW&M    &M&&&KMMMMWMK   &  K   &           &
                  WW&KK        K    &  KKKW      &       &&K   K
                 &WK            M     K&     M   K    K    K
                 W&             K               K
                 W                             K   K

       K
       K W WW WWWKWWKWK WMWMW W  WW& &WWMW& WWKWWWWMWWW MMWW WWWW

.,...,,:::::: ::      :               ,,, :  .         , . :          :.
,,,.,,,: :,,: ::                :              .    : ,::              ,
,::,,,::::,,: ::                   :           :,  :
:::,,:,:::,:   :
,::,,,::::::                      :   :              .
::,,.,,: ::                                                     ,
::,,,,:::::
::,,,,,:: :                                          ,
:::,,,,: ::                                         .          :
: :::::                 ,       ,             :       .,
: :::         :.                              .
:       ,                                    .
  .    .             .                :.                  , :    :
            .,        :                                   ,
                           :                     . ,     :
                   :      .
   :                        ,.               :.,                  ..
   ::                    :: ,                 :                       ,
  :,,                   ,               ,,                     ,  :
 :,.,                   ,  :                                   :.
::,.,:                                          .    ,          , .
::,..::                                             ,          : :.
::,..::  :                                    .   .               :
::,.,:       :               .                       ,    .
:,..,    ::: :: :         : .,     :    : , .                 .,   .
,,,.,:::::,::::       :        ,  ,.    . :                ,:  .    .
,,...,,,...,:,,:    ,         ,:  : .:  ,, .:               : ,     .
... ..:        .     .    : :,  :.          :         ::               :
..      .                       .                                .     :

             ~  ~<<~~~ ~~<<<<*<~~<*<~      ~  ~                  <~~~~
        ~    ~  ~<<<<<~~<*****<~ ~<~         <*      }        <  *<*<<~
             ~  ~<<<<<<<**}}***~~<*               <              *****<~
            ~~~ <*<*****}}}}}}*<~**~            * ~            < }*}}**~
            ~<~~*}}*}*}}}   }}}<<<                  ~             }  }*~
        ~  ~<<<<}}}*}}*}}    }}<~                                     }<
           ~<*<*} }}}}*}      }<                    ~                 }<
         ~ ~<**}   }}***}      }*}                              ~     }<
        ~  <***}   }}<      *~~*}                                      <
 ~     ~~~~<***}    }                                                  *
 ~   ~~<**<**<                                       }<      ~         *
 ~~~~<*<                                  ~            }**             *
~<      }                   ~        }    <           <<~~ * <}   *    *
~~            ~**  ~                                   ~         *     *
<*<~~*}}}***}}}}}             }      }}< }              <          }   }
*<<~~<<<*<<<*** *     ~    ~} }<<*     }}<     } }      }          } * }
<*~ ~<<<*<<***}}          ~~  <  *      < *      *     *         }  }
<<~  <<**<<*}}}            ~                                  *
~~   ~<<*<<*}*}  }       ~  ~~            * }                    <
~    ~~<<<<*}}}  *       }             }    }                    }     }
      ~~~~~<***}                       * *        **~    *    }  ~     <
       ~~~~<*<<} }                       ~            <     * *        <
       ~~ ~~<~<*<                     ~    }         }<*    <      *   <
      ~~~~~~~ ~<~       <}       <*      }~**   *        *    ~        <
     ~~~~   ~  ~      *~}~ *  ~  <     < *   }       <   }   ~         ~
               <     <  *     }  <    *~ } < ~       <       <~        <
                   ~ }   }   ~  *  *  ~      }      }    <   *         ~
        * }     }}~   *}*} ~            <    } ~  }} *  <~     ~
      *

                                                        j     ooj
                                          oj                   Vj
                                              V                Vj
                                               j o              o
                         jjj       U o         U  V             oj jj
                         jjjj    j                               ojjjj
                 j      jjjjjj                     U             ooojj
                jjj      jooojj                                  Voojj
                jjj    o  jj                 UojU               Uooojjj
                jojj             jo U        j V V      V  U VU VVVoooj
                           j     oU         o     o j     V j V VVVVooj
                           o    joV      j    U      U     V   joUVUooj
                       V   V VVojj         V       U U         Vj  oVoj
                    Vo   U UjoVoVoo                  Uo    VUVV     oVo
                  j       U Vo VUVUoV          Uj o  jo           V jVo
               j             o    VUVU    o   j   jo Uj  U            o
                j   o          jj  V UV            U    V     o       oo
               joj              o           o  o UUV U         o       j
               jo              V      UU   U o  VoU U         V        V
               jj         V j           j  U UUVU  Vojojoo    j
                VV     jjVV        V    o   VU U V        VVU
                j     UVUV             Uo  UU V   jV   joUjj    V
                 V     VjV jUUj VoUU o      UU     j    j    UV
                    VVVj   jj jV   UUV  U         Uoo  VV   VU V
                   oVo            V U o       jU UUVU VUV ooU
                j ooj  j Uoo j  V    j        U VVV o oVjj
                VVj   jjV jj     j            VVjjoU jjjo
         j j        V                         o j
             o               U      U                  U    U