;;; Credit crunch model by Peter Thompson __includes ["bdi.nls"] globals [poundvalue stockvalue richamount richpay middleamount middlepay pooramount poorpay importpercent numofcollapsed] breed [families family] breed [banks bank] banks-own [beliefs intentions reserves classtype bankx banky collapsed] families-own [beliefs intentions banknumber class salary wallet account hungry breadtype homeposx homeposy loanday bankrupt] patches-own [] to setup-families create-families people [ set shape "person" rand-xy-co set color green set homeposx pxcor set homeposy pycor set beliefs ["bankcollapse" "false"] set intentions [] set wallet random 10 set account starting + random 1000 ; start with a varied amount in the account. set banknumber people + random numofbanks set breadtype -1 if importpercent > 0 [ set breadtype 0 set importpercent importpercent - 1 ] if breadtype = -1 and importpercent <= 0 [ set breadtype 1 ] set hungry 0 set salary 0 set class "none" if richamount > 0 [ set salary richpay set richamount richamount - 1 set class "rich" ] if salary = 0 and middleamount > 0 [ set salary middlepay set middleamount middleamount - 1 set class "middle" ] if salary = 0 and pooramount > 0 [ set salary poorpay set pooramount pooramount - 1 set class "poor" ] set loanday -1 set bankrupt false ] end to setup-banks create-banks numofbanks [ set shape "house" rand-xy-co set bankx xcor set banky ycor setxy bankx banky set color white set beliefs [] set intentions [] set reserves random 50000 + 50000 set collapsed false ] end to switchbank ; this gets called upon a belief that states that the bank is bust. ; from bust bank to one that is not. if wallet < 10 ;;;;;;;;;;;;; need a better fix here [ set bankrupt true set color grey ] if wallet >= 10 [ if numofcollapsed < numofbanks and ticks < duration [ find-collapsed let newbank (people) while [[collapsed] of bank (newbank) = false] [ if newbank + 1 <= people + numofbanks [ set newbank newbank + 1 ] if newbank + 1 > people + numofbanks [ set newbank (people) ] ] set banknumber (newbank) ; put what is in wallet into new bank set account wallet set wallet 0 ] ] end to bankrun let closeacc account let chance 100 / selfinterested let roll random chance if roll = 1 or selfinterested = 100 [ if [reserves] of bank banknumber >= closeacc [ set wallet wallet + closeacc ask bank banknumber [set reserves reserves - closeacc] set account 0 ] ] end to buybread if wallet >= 2.5 ;;;;;;;;;;; THIS WILL BE REPLACED BY A BELIEF [ if breadtype = 1 [ ; british bread set poundvalue poundvalue + 0.000001 set wallet wallet - 2.5 set hungry 0 ] if breadtype = 0 [ ; imported bread set poundvalue poundvalue - 0.000005 set wallet wallet - 1.8 set hungry 0 ] ] end to withdraw ask bank banknumber [set reserves reserves - 10] set wallet 10 set account account - 10 if showwithdrawlinks = true [ create-link-to bank banknumber[set color red] ] end to deposit let amount salary ask bank banknumber [set reserves reserves + amount] set account account + amount if showdepositlinks = true [ create-link-to bank banknumber[set color green] ] end to loan ask bank banknumber [set reserves reserves - 200] set account account + 200 set loanday ticks create-link-to bank banknumber[set color blue] if showloanlabels = true [ set label "loan" ] if loanday != -1 and ticks = loanday + 30 [ if account >= 220 [ ask bank banknumber[set reserves reserves + 220] set account account - 220 set loanday -1 set label "" ] if account < 220 [ set bankrupt true set color grey ] ] end to rand-xy-co let x 0 let y 0 loop [ set x random-pxcor set y random-pycor if not any? turtles-on patch x y and not (abs x < 4 and abs y < 4) [setxy x y stop] ] end to setup clear-all ;; clear the world ;set duration 1187 set poundvalue 1.0001 set richpay 30 set middlepay 7 set poorpay 3 set richamount people * 0.2 set middleamount people * 0.6 set pooramount people * 0.2 set importpercent importpercentin set numofcollapsed 0 setup-plot setup-families setup-banks end to go if ticks < duration [ ask banks [set reserves (reserves * (poundvalue - 1)) / 10 + reserves ] update-beliefs ask families [family-behaviour] ask families [set hungry hungry + 1] ; needs proper implementation ask banks [ask my-in-links [ die ]] update-plot tick ; Pass one day ] if numofcollapsed = numofbanks [stop] end to family-behaviour update-intentions execute-intentions ; many times for there may be many intentions on the stack execute-intentions execute-intentions execute-intentions execute-intentions execute-intentions end to find-collapsed let numofcollapsedcount 0 ask banks [ if reserves <= 0 [ set pcolor red set numofcollapsedcount numofcollapsedcount + 1 set collapsed true ] ] set numofcollapsed numofcollapsedcount if numofcollapsed = numofbanks [stop] end to update-beliefs let collapsedchange numofcollapsed find-collapsed if collapsedchange != numofcollapsed [ set poundvalue poundvalue - 0.0006 ] end to update-intentions if wallet >= 2.5 [ add-intention "buybread" "true" ] if bankrupt = false [ if [reserves] of bank banknumber >= 0 and [collapsed] of bank banknumber = false [ if wallet < 2.5 [ add-intention "withdraw" "true" ] ] ] if bankrupt = false [ if wallet >= 8 [ add-intention "deposit" "true" ] ] if [collapsed] of bank banknumber = false [ if account < 1000 and bankrupt = false [ add-intention "loan" "true" ] ] if [reserves] of bank banknumber <= 12000 [ if account > 0 [ add-intention "bankrun" "true" ] ] if [collapsed] of bank banknumber = true [ add-intention "switchbank" "true" ] end to setup-plot set-current-plot "Average Bank Reserves" end to update-plot set-current-plot-pen "reserves" plot mean [reserves] of banks end @#$#@#$#@ GRAPHICS-WINDOW 211 11 728 471 19 16 13.0 1 8 1 1 1 0 1 1 1 -19 19 -16 16 0 0 1 days BUTTON 1 11 64 44 NIL setup NIL 1 T OBSERVER NIL NIL NIL NIL BUTTON 65 11 128 44 step go NIL 1 T OBSERVER NIL NIL NIL NIL BUTTON 129 11 210 44 go (loop) go T 1 T OBSERVER NIL NIL NIL NIL MONITOR 130 408 208 453 poundvalue poundvalue 17 1 11 PLOT 729 11 996 471 Average Bank Reserves Days average reserves 0.0 10.0 0.0 10000.0 true false PENS "reserves" 1.0 0 -10899396 false SWITCH 1 278 144 311 show-intentions show-intentions 1 1 -1000 SLIDER 1 44 173 77 people people 50 450 309 1 1 NIL HORIZONTAL SLIDER 1 110 173 143 importpercentin importpercentin 0 100 50 1 1 % HORIZONTAL SLIDER 1 77 173 110 numofbanks numofbanks 1 30 24 1 1 NIL HORIZONTAL SLIDER 1 143 173 176 starting starting 2500 3500 2500 10 1 £ HORIZONTAL SWITCH 1 244 149 277 showdepositlinks showdepositlinks 0 1 -1000 MONITOR 1 408 129 453 Collapsed banks numofcollapsed 17 1 11 SWITCH 1 312 159 345 showwithdrawlinks showwithdrawlinks 0 1 -1000 SWITCH 1 346 140 379 showloanlabels showloanlabels 0 1 -1000 SLIDER 1 176 173 209 selfinterested selfinterested 1 100 82 1 1 % HORIZONTAL SLIDER 173 44 206 194 duration duration 1000 9000 6450 10 1 days VERTICAL @#$#@#$#@ WHAT IS IT? ----------- I have decided to model the credit crunch from its early stages where the banks signed many irresponsible loans in order to boost its profits, through to where these loans defaulted, to where the bank's collapse because of the worsening economy and weakening of the pound. The dynamic model allows for many input scenarios where the culprits that caused the credit crunch can be identified and focussed on, to find solutions as to how the crisis could have been prevented, or indeed can be prevented from a specific moment onwards. HOW IT WORKS ------------ The model view shows people and their banks interacting, red arrows showing withdrawals and green arrows showing deposits, blue arrows are loan agreements. If a person takes out a loan, they get a label of "loan" until this is paid off; the loan period is 30 days. Should a person become bankrupt, their figure becomes grey and no longer interacts with a bank, any loans they may have default. Bank can collapse when they run out of reserves, and their patch colour (background) becomes red, there will be no more transactions with people once the bank has collapsed. Although the term people has been used throughout the report, agents can be referred to as families or even companies, which can be pushed into administration when their account is empty. Every one of these entities has a bank account with a specific starting value, they have a mentality to import food or buy British made food, their mentality can also be altered in terms of engaging in bank runs. HOW TO USE IT ------------- Select the sliders to the desired position, click setup and go (loop). THINGS TO NOTICE ---------------- Fine tuning can provide many different models for the credit crunch. THINGS TO TRY ------------- People: 309 Banks: 24 Import percentage: 50% Starting: £2500 Self Interested: 82% Duration: 6000 days EXTENDING THE MODEL ------------------- We could extend the model by showing a recovery after the credit crunch. I would have like to have made the actions of agents more transparent to other agents, effectively modelling the credit crunch is a more effective manner as it is argued that the media and word of mouth played a big part in the crisis, resulting in problems such as less spending, spending on cheaper and imported goods, leading to less money being pumped into the economy, and engaging in bank runs collapsing many banks. CREDITS AND REFERENCES ---------------------- [1] Anand S. Rao Australian Artificial Intelligence Institute Michael P. George. BDI Agents From Theory to Practice http://www.agent.ai/doc/upload/200302/rao95.pdf [2] Ilias Sakellariou NetLogoBDI Extension http://users.uom.gr/\~iliass/projects/NetLogo/ [3] Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo. Center for Connected Learning and Computer-Based Modeling. Northwestern University, Evanston, IL. @#$#@#$#@ default true 0 Polygon -7500403 true true 150 5 40 250 150 205 260 250 airplane true 0 Polygon -7500403 true true 150 0 135 15 120 60 120 105 15 165 15 195 120 180 135 240 105 270 120 285 150 270 180 285 210 270 165 240 180 180 285 195 285 165 180 105 180 60 165 15 arrow true 0 Polygon -7500403 true true 150 0 0 150 105 150 105 293 195 293 195 150 300 150 box false 0 Polygon -7500403 true true 150 285 285 225 285 75 150 135 Polygon -7500403 true true 150 135 15 75 150 15 285 75 Polygon -7500403 true true 15 75 15 225 150 285 150 135 Line -16777216 false 150 285 150 135 Line -16777216 false 150 135 15 75 Line -16777216 false 150 135 285 75 bug true 0 Circle -7500403 true true 96 182 108 Circle -7500403 true true 110 127 80 Circle -7500403 true true 110 75 80 Line -7500403 true 150 100 80 30 Line -7500403 true 150 100 220 30 butterfly true 0 Polygon -7500403 true true 150 165 209 199 225 225 225 255 195 270 165 255 150 240 Polygon -7500403 true true 150 165 89 198 75 225 75 255 105 270 135 255 150 240 Polygon -7500403 true true 139 148 100 105 55 90 25 90 10 105 10 135 25 180 40 195 85 194 139 163 Polygon -7500403 true true 162 150 200 105 245 90 275 90 290 105 290 135 275 180 260 195 215 195 162 165 Polygon -16777216 true false 150 255 135 225 120 150 135 120 150 105 165 120 180 150 165 225 Circle -16777216 true false 135 90 30 Line -16777216 false 150 105 195 60 Line -16777216 false 150 105 105 60 car false 0 Polygon -7500403 true true 300 180 279 164 261 144 240 135 226 132 213 106 203 84 185 63 159 50 135 50 75 60 0 150 0 165 0 225 300 225 300 180 Circle -16777216 true false 180 180 90 Circle -16777216 true false 30 180 90 Polygon -16777216 true false 162 80 132 78 134 135 209 135 194 105 189 96 180 89 Circle -7500403 true true 47 195 58 Circle -7500403 true true 195 195 58 circle false 0 Circle -7500403 true true 0 0 300 circle 2 false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 cow false 0 Polygon -7500403 true true 200 193 197 249 179 249 177 196 166 187 140 189 93 191 78 179 72 211 49 209 48 181 37 149 25 120 25 89 45 72 103 84 179 75 198 76 252 64 272 81 293 103 285 121 255 121 242 118 224 167 Polygon -7500403 true true 73 210 86 251 62 249 48 208 Polygon -7500403 true true 25 114 16 195 9 204 23 213 25 200 39 123 cylinder false 0 Circle -7500403 true true 0 0 300 dot false 0 Circle -7500403 true true 90 90 120 face happy false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 255 90 239 62 213 47 191 67 179 90 203 109 218 150 225 192 218 210 203 227 181 251 194 236 217 212 240 face neutral false 0 Circle -7500403 true true 8 7 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Rectangle -16777216 true false 60 195 240 225 face sad false 0 Circle -7500403 true true 8 8 285 Circle -16777216 true false 60 75 60 Circle -16777216 true false 180 75 60 Polygon -16777216 true false 150 168 90 184 62 210 47 232 67 244 90 220 109 205 150 198 192 205 210 220 227 242 251 229 236 206 212 183 fish false 0 Polygon -1 true false 44 131 21 87 15 86 0 120 15 150 0 180 13 214 20 212 45 166 Polygon -1 true false 135 195 119 235 95 218 76 210 46 204 60 165 Polygon -1 true false 75 45 83 77 71 103 86 114 166 78 135 60 Polygon -7500403 true true 30 136 151 77 226 81 280 119 292 146 292 160 287 170 270 195 195 210 151 212 30 166 Circle -16777216 true false 215 106 30 flag false 0 Rectangle -7500403 true true 60 15 75 300 Polygon -7500403 true true 90 150 270 90 90 30 Line -7500403 true 75 135 90 135 Line -7500403 true 75 45 90 45 flower false 0 Polygon -10899396 true false 135 120 165 165 180 210 180 240 150 300 165 300 195 240 195 195 165 135 Circle -7500403 true true 85 132 38 Circle -7500403 true true 130 147 38 Circle -7500403 true true 192 85 38 Circle -7500403 true true 85 40 38 Circle -7500403 true true 177 40 38 Circle -7500403 true true 177 132 38 Circle -7500403 true true 70 85 38 Circle -7500403 true true 130 25 38 Circle -7500403 true true 96 51 108 Circle -16777216 true false 113 68 74 Polygon -10899396 true false 189 233 219 188 249 173 279 188 234 218 Polygon -10899396 true false 180 255 150 210 105 210 75 240 135 240 house false 0 Rectangle -7500403 true true 45 120 255 285 Rectangle -16777216 true false 120 210 180 285 Polygon -7500403 true true 15 120 150 15 285 120 Line -16777216 false 30 120 270 120 leaf false 0 Polygon -7500403 true true 150 210 135 195 120 210 60 210 30 195 60 180 60 165 15 135 30 120 15 105 40 104 45 90 60 90 90 105 105 120 120 120 105 60 120 60 135 30 150 15 165 30 180 60 195 60 180 120 195 120 210 105 240 90 255 90 263 104 285 105 270 120 285 135 240 165 240 180 270 195 240 210 180 210 165 195 Polygon -7500403 true true 135 195 135 240 120 255 105 255 105 285 135 285 165 240 165 195 line true 0 Line -7500403 true 150 0 150 300 line half true 0 Line -7500403 true 150 0 150 150 pentagon false 0 Polygon -7500403 true true 150 15 15 120 60 285 240 285 285 120 person false 0 Circle -7500403 true true 110 5 80 Polygon -7500403 true true 105 90 120 195 90 285 105 300 135 300 150 225 165 300 195 300 210 285 180 195 195 90 Rectangle -7500403 true true 127 79 172 94 Polygon -7500403 true true 195 90 240 150 225 180 165 105 Polygon -7500403 true true 105 90 60 150 75 180 135 105 plant false 0 Rectangle -7500403 true true 135 90 165 300 Polygon -7500403 true true 135 255 90 210 45 195 75 255 135 285 Polygon -7500403 true true 165 255 210 210 255 195 225 255 165 285 Polygon -7500403 true true 135 180 90 135 45 120 75 180 135 210 Polygon -7500403 true true 165 180 165 210 225 180 255 120 210 135 Polygon -7500403 true true 135 105 90 60 45 45 75 105 135 135 Polygon -7500403 true true 165 105 165 135 225 105 255 45 210 60 Polygon -7500403 true true 135 90 120 45 150 15 180 45 165 90 sheep false 0 Rectangle -7500403 true true 151 225 180 285 Rectangle -7500403 true true 47 225 75 285 Rectangle -7500403 true true 15 75 210 225 Circle -7500403 true true 135 75 150 Circle -16777216 true false 165 76 116 square false 0 Rectangle -7500403 true true 30 30 270 270 square 2 false 0 Rectangle -7500403 true true 30 30 270 270 Rectangle -16777216 true false 60 60 240 240 star false 0 Polygon -7500403 true true 151 1 185 108 298 108 207 175 242 282 151 216 59 282 94 175 3 108 116 108 target false 0 Circle -7500403 true true 0 0 300 Circle -16777216 true false 30 30 240 Circle -7500403 true true 60 60 180 Circle -16777216 true false 90 90 120 Circle -7500403 true true 120 120 60 tree false 0 Circle -7500403 true true 118 3 94 Rectangle -6459832 true false 120 195 180 300 Circle -7500403 true true 65 21 108 Circle -7500403 true true 116 41 127 Circle -7500403 true true 45 90 120 Circle -7500403 true true 104 74 152 triangle false 0 Polygon -7500403 true true 150 30 15 255 285 255 triangle 2 false 0 Polygon -7500403 true true 150 30 15 255 285 255 Polygon -16777216 true false 151 99 225 223 75 224 truck false 0 Rectangle -7500403 true true 4 45 195 187 Polygon -7500403 true true 296 193 296 150 259 134 244 104 208 104 207 194 Rectangle -1 true false 195 60 195 105 Polygon -16777216 true false 238 112 252 141 219 141 218 112 Circle -16777216 true false 234 174 42 Rectangle -7500403 true true 181 185 214 194 Circle -16777216 true false 144 174 42 Circle -16777216 true false 24 174 42 Circle -7500403 false true 24 174 42 Circle -7500403 false true 144 174 42 Circle -7500403 false true 234 174 42 turtle true 0 Polygon -10899396 true false 215 204 240 233 246 254 228 266 215 252 193 210 Polygon -10899396 true false 195 90 225 75 245 75 260 89 269 108 261 124 240 105 225 105 210 105 Polygon -10899396 true false 105 90 75 75 55 75 40 89 31 108 39 124 60 105 75 105 90 105 Polygon -10899396 true false 132 85 134 64 107 51 108 17 150 2 192 18 192 52 169 65 172 87 Polygon -10899396 true false 85 204 60 233 54 254 72 266 85 252 107 210 Polygon -7500403 true true 119 75 179 75 209 101 224 135 220 225 175 261 128 261 81 224 74 135 88 99 wheel false 0 Circle -7500403 true true 3 3 294 Circle -16777216 true false 30 30 240 Line -7500403 true 150 285 150 15 Line -7500403 true 15 150 285 150 Circle -7500403 true true 120 120 60 Line -7500403 true 216 40 79 269 Line -7500403 true 40 84 269 221 Line -7500403 true 40 216 269 79 Line -7500403 true 84 40 221 269 x false 0 Polygon -7500403 true true 270 75 225 30 30 225 75 270 Polygon -7500403 true true 30 75 75 30 270 225 225 270 @#$#@#$#@ NetLogo 4.1 @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ @#$#@#$#@ default 0.0 -0.2 0 1.0 0.0 0.0 1 1.0 0.0 0.2 0 1.0 0.0 link direction true 0 Line -7500403 true 150 150 90 180 Line -7500403 true 150 150 210 180 @#$#@#$#@ 0 @#$#@#$#@