RuneScape:Grand Exchange Market Watch/Adjustments

Indices must be adapted constantly to changing conditions so they can fulfill their purpose as measuring instruments for the Grand Exchange Market Watch. Price and volume data must also be adjusted on occasions where there is missing data, data vandalism in the wiki, or when the official Grand Exchange Database produces incomplete or erroneous data.

This page lists the methods and calculations used for the adjustments made to the indices and the data. For general information regarding the Grand Exchange Market Watch, see Grand Exchange Market Watch/FAQ.

Indices

2008

10 January 2008

Adjusted index: Common Trade Index Adjustment date: 10 January 2008 Affected templates: Template:GE Common Trade Index and Template:GE Common Trade Index/Diff Added item(s): 8 — Mithril ore, Raw swordfish, Raw monkfish, Snape grass, Clean ranarr, Clean kwuarm, Clean snapdragon, Vial of water Removed item(s): None Items before adjustment: 15 Items after adjustment: 23 Divisor before adjustment: 14.464460143296 Divisor after adjustment: 21.791759207424 Item Base date Base price Price on adjustment date Comments Coal ca. December 2007 159 Unknown Unchanged Steel bar 540 Gold ore 528 Nature rune 271 Death rune 299 Pure essence 80 Yew logs 411 Magic logs 1,222 Cowhide 109 Flax 70 Soft clay 207 Limpwurt root 646 Law rune 303 Big bones 419 Raw lobster 237 Mithril ore – – 315 Added item Raw swordfish 237 Raw monkfish 350 Snape grass 428 Clean ranarr 5,959 Clean kwuarm 3,030 Clean snapdragon 6,885 Vial of water 98

2011

14 October 2011

Adjusted index: Rune Index Adjustment date: 14 October 2011 Affected templates: Template:GE Rune Index and Template:GE Rune Index/Diff Added item(s): Armadyl rune Removed item(s): None Items before adjustment: 14 Items after adjustment: 15 Divisor before adjustment: 14.000 Divisor after adjustment:15.5671 Item Base date Base price Price on adjustment date Comments Air rune 15 December 2007 11 6 Unchanged Mind rune 10 3 Water rune 15 6 Earth rune 11 13 Fire rune 10 4 Body rune 9 5 Cosmic rune 140 107 Chaos rune 102 38 Nature rune 258 100 Law rune 304 158 Death rune 299 181 Astral rune 132 81 Blood rune 336 211 Soul rune 335 556 Armadyl rune – – 1,817 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 14.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{6}{11} + \frac{3}{10} + \frac{6}{15} + \dots + \frac{556}{335} \\ & = 8.93366198 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 8.93366198 - 0 + 1 \\ & = 9.933661982 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 14.0000 \times \frac{9.93366198}{8.93366198} \\ & = 15.5671 \text{ (4 d.p.)} \end{align}$

6 November 2011

Adjusted index: Herb Index Adjustment date: 6 November 2011 Affected templates: Template:GE Herb Index and Template:GE Herb Index/Diff Added item(s): Grimy fellstalk, Clean fellstalk Removed item(s): None Items before adjustment: 32 Items after adjustment: 34 Divisor before adjustment: 32.0000 Divisor after adjustment: 33.2409 Item Base date Base price Price on adjustment date Comments Grimy guam 9 June 2009 490 121 Unchanged Grimy marrentill 192 25 Grimy tarromin 216 121 Grimy harralander 787 100 Grimy ranarr 7,654 4,032 Grimy toadflax 2,315 3,637 Grimy irit 1,552 1,172 Grimy wergali 1,800 2,450 Grimy spirit weed 1,917 2,658 Grimy avantoe 1,591 3,293 Grimy kwuarm 2,850 1,356 Grimy snapdragon 9,720 5,224 Grimy cadantine 1,234 1,186 Grimy lantadyme 1,272 5,006 Grimy dwarf weed 2,042 4,744 Grimy torstol 2,980 25,300 Clean guam 481 126 Clean marrentill 101 16 Clean tarromin 193 143 Clean harralander 791 100 Clean ranarr 7,719 3,867 Clean toadflax 2,362 3,644 Clean irit 1,795 1,232 Clean wergali 2,000 2,331 Clean spirit weed 1,888 2,725 Clean avantoe 1,593 3,253 Clean kwuarm 2,881 1,389 Clean snapdragon 9,726 5,402 Clean cadantine 1,245 1,206 Clean lantadyme 1,319 5,267 Clean dwarf weed 2,070 4,668 Clean torstol 2,762 25,400 Grimy fellstalk – – 1,799 Added item Clean fellstalk 1,437 Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 32.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{121}{490} + \frac{25}{192} + \frac{121}{216} + \dots + \frac{25,400}{2,762} \\ & = 51.57722802 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 51.57722802 - 0 + 2 \\ & = 53.57722802 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 32.0000 \times \frac{53.57722802}{51.57722802} \\ & = 33.2409 \text{ (4 d.p.)} \end{align}$

2012

12 February 2012

Adjusted index: Common Trade Index Adjustment date: 12 February 2012 Affected templates: Template:GE Common Trade Index and Template:GE Common Trade Index/Diff Added item(s): 10 — Abyssal whip, Dragon boots, Rune armour set (lg), Red chinchompa, Oak plank, Shark, Green dragonhide, Dragon bones, Cannonball, Dragonfire shield Removed item(s): 6 — Mithril ore, Law rune, Big bones, Raw swordfish, Vial of water, Clean ranarr Items before adjustment: 23 Items after adjustment: 27 Divisor before adjustment: 21.791759207424 Divisor after adjustment: 23.9535 Item Base date Base price Price on adjustment date Comments Coal ca. December 2007 159 320 Unchanged Steel bar 540 1,335 Gold ore 528 304 Nature rune 271 226 Death rune 299 452 Pure essence 80 125 Yew logs 411 522 Magic logs 1,222 1,592 Cowhide 109 513 Flax 70 72 Soft clay 207 541 Limpwurt root 646 2,060 Raw lobster 237 285 Raw monkfish 10 January 2008 350 601 Snape grass 428 314 Clean snapdragon 6,885 9,866 Clean kwuarm 3,030 1,828 Law rune ca. December 2007 303 363 Removed item Big bones 419 621 Raw swordfish 10 January 2008 325 492 Mithril ore 315 349 Vial of water 98 36 Clean ranarr 5,959 4,958 Abyssal whip – – 420,951 Added item Dragon boots 103,701 Rune armour set (lg) 136,531 Red chinchompa 1,592 Oak plank 639 Shark 1,715 Green dragonhide 2,196 Dragon bones 3,962 Cannonball 407 Dragonfire shield 7,946,801 Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 21.791759207424$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \left (\frac{320}{159} + \frac{1,335}{540} + \dots + \frac{1,828}{3,030} \right ) + \left (\frac{363}{303} + \frac{621}{419} + \dots + \frac{4,958}{5,959} \right ) \\ & = 35.26980062 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 35.26980062 - \left ( \frac{363}{303} + \frac{621}{419} + \dots + \frac{4,958}{5,959} \right ) + 10 \\ & = 38.76853218 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 21.791759207424 \times \frac{38.76853218}{35.26980062} \\ & = 23.9535 \text{ (4 d.p.)} \end{align}$

29 September 2012

Adjusted index: Discontinued Rare Index Adjustment date: 29 September 2012 Affected templates: Template:GE Discontinued Rare Index and Template:GE Discontinued Rare Index/Diff Added item(s): Fish mask Removed item(s): None Items before adjustment: 15 Items after adjustment: 16 Divisor before adjustment: 15.0000 Divisor after adjustment: 15.0826 Item Base date Base price Price on adjustment date Comments Christmas cracker 31 December 2008 688,800,000 2,146,908,554 Unchanged Blue partyhat 340,100,000 2,147,483,647 Green partyhat 114,800,000 1,124,859,082 Purple partyhat 83,100,000 895,254,988 Red partyhat 129,400,000 1,232,179,013 White partyhat 183,300,000 1,652,939,303 Yellow partyhat 96,300,000 948,567,763 Pumpkin 5,300,000 165,935,075 Easter egg 4,300,000 56,837,419 Blue h'ween mask 12,800,000 112,172,382 Green h'ween mask 10,600,000 90,439,249 Red h'ween mask 17,300,000 149,074,067 Santa hat 14,800,000 116,884,816 Disk of returning 4,700,000 171,076,782 Half full wine jug 31,100,000 261,000,577 Fish mask – – 4,555,462 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{2,146,908,554}{688,800,000} + \frac{2,147,483,647}{340,100,000} + \frac{1,124,859,082}{114,800,000} + \dots + \frac{261,000,577}{31,100,000} \\ & = 181.52107486 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 181.52107486 - 0 + 1 \\ & = 182.52107486 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.0000 \times \frac{182.52107486}{181.52107486} \\ & = 15.0826 \text{ (4 d.p.)} \end{align}$

2013

20 January 2013

Adjusted index: Discontinued Rare Index Adjustment date: 20 January 2013 Affected templates: Template:GE Discontinued Rare Index and Template:GE Discontinued Rare Index/Diff Added item(s): Christmas tree hat Removed item(s): None Items before adjustment: 16 Items after adjustment: 17 Divisor before adjustment: 15.0826 Divisor after adjustment: 15.1547 Item Base date Base price Price on adjustment date Comments Christmas cracker 31 December 2008 688,800,000 2,147,476,523 Unchanged Blue partyhat 340,100,000 2,147,483,647 Green partyhat 114,800,000 1,439,919,758 Purple partyhat 83,100,000 1,194,593,128 Red partyhat 129,400,000 1,588,813,583 White partyhat 183,300,000 2,115,586,339 Yellow partyhat 96,300,000 1,288,308,900 Pumpkin 5,300,000 153,543,323 Easter egg 4,300,000 73,851,614 Blue h'ween mask 12,800,000 130,080,270 Green h'ween mask 10,600,000 107,141,857 Red h'ween mask 17,300,000 168,034,752 Santa hat 14,800,000 130,038,816 Disk of returning 4,700,000 193,631,082 Half full wine jug 31,100,000 282,814,298 Fish mask 29 September 2012 4,555,462 1,778,504 Christmas tree hat – – 2,295,576 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.0826$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{2,146,908,554}{688,800,000} + \frac{2,147,483,647}{340,100,000} + \frac{1,439,919,758}{114,800,000} + \dots + \frac{1,778,504}{4,555,462} \\ & = 209.14534690 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 209.14534690 - 0 + 1 \\ & = 210.14534690 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.0826 \times \frac{210.14534690}{209.14534690} \\ & = 15.1547 \text{ (4 d.p.)} \end{align}$

23 July 2013

Adjusted index: Discontinued Rare Index Adjustment date: 23 July 2013 Affected templates: Template:GE Discontinued Rare Index and Template:GE Discontinued Rare Index/Diff Added item(s): Crown of Seasons Removed item(s): None Items before adjustment: 17 Items after adjustment: 18 Divisor before adjustment: 15.1547 Divisor after adjustment: 15.2129 Item Base date Base price Price on adjustment date Comments Christmas cracker 31 December 2008 688,800,000 2,147,483,557 Unchanged Blue partyhat 340,100,000 2,147,483,647 Green partyhat 114,800,000 1,845,813,270 Purple partyhat 83,100,000 1,514,338,96 Red partyhat 129,400,000 2,100,264,784 White partyhat 183,300,000 2,147,483,598 Yellow partyhat 96,300,000 1,607,195,89 Pumpkin 5,300,000 177,606,966 Easter egg 4,300,000 82,884,794 Blue h'ween mask 12,800,000 169,489,376 Green h'ween mask 10,600,000 129,808,159 Red h'ween mask 17,300,000 234,599,317 Santa hat 14,800,000 149,818,733 Disk of returning 4,700,000 226,927,013 Half full wine jug 31,100,000 320,604,356 Fish mask 29 September 2012 4,555,462 1,446,274 Christmas tree hat 20 January 2013 2,295,576 26,024,637 Crown of Seasons – – 8,307,542 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.1547$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{2,147,483,557}{688,800,000} + \frac{2,147,483,647}{340,100,000} + \frac{1,845,813,270}{114,800,000} + \dots + \frac{26,024,637}{2,295,576} \\ & = 260.57227963 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 260.57227963 - 0 + 1 \\ & = 261.57227963 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.1547 \times \frac{261.57227963}{260.57227963} \\ & = 15.2129 \text{ (4 d.p.)} \end{align}$

8 November 2013

Adjusted index: Log Index Adjustment date: 8 November 2013 Affected templates: Template:GE Log Index and Template:GE Log Index/Diff Added item(s): Elder logs Removed item(s): None Items before adjustment: 10 Items after adjustment: 11 Divisor before adjustment: 10.0000 Divisor after adjustment: 10.3117 Item Base date Base price Price on adjustment date Comments Logs 19 December 2007 34 28 Unchanged Achey tree logs 40 39 Oak logs 18 12 Willow logs 22 20 Teak logs 136 71 Maple logs 46 30 Mahogany logs 173 392 Arctic pine logs 855 57 Yew logs 413 526 Magic logs 1,221 1,646 Elder logs – – 3,952 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 10.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{280}{34} + \frac{399}{40} + \frac{123}{18} + \dots + \frac{1,646}{1,221} \\ & = 32.08119681 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 32.08119681 - 0 + 1 \\ & = 33.08119681 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 10.0000 \times \frac{33.08119681}{32.08119681} \\ & = 10.3117 \text{ (4 d.p.)} \end{align}$

2014

20 January 2014

Adjusted index: Discontinued Rare Index Adjustment date: 20 January 2014 Affected templates: Template:GE Discontinued Rare Index and Template:GE Discontinued Rare Index/Diff Added item(s): Black Santa hat Removed item(s): None Items before adjustment: 18 Items after adjustment: 19 Divisor before adjustment: 15.2129 Divisor after adjustment: 15.2787 Item Base date Base price Price on adjustment date Comments Christmas cracker 31 December 2008 688,800,000 2,147,483,632 Unchanged Blue partyhat 340,100,000 2,147,483,647 Green partyhat 114,800,000 1,490,829,327 Purple partyhat 83,100,000 1,279,369,134 Red partyhat 129,400,000 1,696,893,747 White partyhat 183,300,000 2,146,833,194 Yellow partyhat 96,300,000 1,335,202,311 Pumpkin 5,300,000 174,290,712 Easter egg 4,300,000 70,272,905 Blue h'ween mask 12,800,000 132,769,255 Green h'ween mask 10,600,000 110,890,723 Red h'ween mask 17,300,000 185,134,793 Santa hat 14,800,000 135,913,306 Disk of returning 4,700,000 223,384,911 Half full wine jug 31,100,000 333,709,743 Fish mask 29 September 2012 4,555,462 944,822 Christmas tree hat 20 January 2013 2,295,576 12,593,302 Crown of Seasons 23 July 2013 8,307,542 3,926,892 Black Santa hat – – 222,967,707 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.2129$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{2,147,483,557}{688,800,000} + \frac{2,147,483,647}{340,100,000} + \frac{1,490,829,327}{114,800,000} + \dots + \frac{12,593,302}{2,295,576} + \frac{3,926,892}{8,307,542} \\ & = 230.87579845 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 230.87579845 - 0 + 1 \\ & = 231.87579845 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.2129 \times \frac{231.87579845}{230.87579845} \\ & = 15.2787 \text{ (4 d.p.)} \end{align}$

19 June 2014

Adjusted index: Discontinued Rare Index Adjustment date: 19 June 2014 Affected templates: Template:GE Discontinued Rare Index and Template:GE Discontinued Rare Index/Diff Added item(s): Cloak of Seasons Removed item(s): None Items before adjustment: 19 Items after adjustment: 20 Divisor before adjustment: 15.2787 Divisor after adjustment: 15.3476 Item Base date Base price Price on adjustment date Comments Christmas cracker 31 December 2008 688,800,000 2,147,483,644 Unchanged Blue partyhat 340,100,000 2,147,483,647 Green partyhat 114,800,000 1,512,978,741 Purple partyhat 83,100,000 1,242,748,792 Red partyhat 129,400,000 1,706,390,538 White partyhat 183,300,000 2,147,481,758 Yellow partyhat 96,300,000 1,325,097,236 Pumpkin 5,300,000 157,608,053 Easter egg 4,300,000 62,666,643 Blue h'ween mask 12,800,000 121,249,470 Green h'ween mask 10,600,000 98,258,298 Red h'ween mask 17,300,000 170,663,885 Santa hat 14,800,000 125,533,632 Disk of returning 4,700,000 211,466,440 Half full wine jug 31,100,000 348,603,157 Fish mask 29 September 2012 4,555,462 669,574 Christmas tree hat 20 January 2013 2,295,576 12,559,556 Crown of Seasons 23 July 2013 8,307,542 4,555,009 Black Santa hat 20 January 2013 222,967,707 410,924,805 Cloak of Seasons – – 7,614,236 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.2787$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{2,147,483,644}{688,800,000} + \frac{2,147,483,647}{340,100,000} + \frac{1,512,978,741}{114,800,000} + \dots + \frac{4,555,009}{8,307,542} + \frac{410,924,805}{222,967,707} \\ & = 221.84047459 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 221.84047459 - 0 + 1 \\ & = 222.84047459 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.2787 \times \frac{222.84047459}{221.84047459} \\ & = 15.3476 \text{ (4 d.p.)} \end{align}$

30 August 2014

Adjusted index: Rune Index Adjustment date: 30 August 2014 Affected templates: Template:GE Rune Index and Template:GE Rune Index/Diff Added item(s): Steam rune, Mist rune, Dust rune, Smoke rune, Mud rune, Lava rune Removed item(s): None Items before adjustment: 15 Items after adjustment: 21 Divisor before adjustment: 15.5671 Divisor after adjustment: 21.2740 Item Base date Base price Price on adjustment date Comments Air rune 15 December 2007 11 19 Unchanged Mind rune 10 6 Water rune 15 26 Earth rune 11 14 Fire rune 10 22 Body rune 9 8 Cosmic rune 140 245 Chaos rune 102 41 Nature rune 258 263 Law rune 304 281 Death rune 299 163 Astral rune 132 245 Blood rune 336 261 Soul rune 335 153 Armadyl rune 14 October 2011 1,817 389 Steam rune – – 37 Added item Mist rune 348 Dust rune 66 Smoke rune 314 Mud rune 775 Lava rune 49 Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.5671$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{19}{11} + \frac{6}{10} + \frac{26}{15} + \dots + \frac{153}{335} + \frac{389}{1,817} \\ & = 16.36670735 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 16.36670735 - 0 + 6 \\ & = 22.36670735 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.5671 \times \frac{22.36670735}{16.36670735} \\ & = 21.2740 \text{ (4 d.p.)} \end{align}$

30 December 2014

Adjusted index: Discontinued Rare Index Adjustment date: 30 December 2014 Affected templates: Template:GE Discontinued Rare Index and Template:GE Discontinued Rare Index/Diff Added item(s): Rubber turkey, Off-hand rubber turkey, Christmas scythe, Holly wreath Removed item(s): None Items before adjustment: 20 Items after adjustment: 24 Divisor before adjustment: 15.3476 Divisor after adjustment: 15.6373 Item Base date Base price Price on adjustment date Comments Christmas cracker 31 December 2008 688,800,000 2,147,483,644 Unchanged Blue partyhat 340,100,000 2,147,483,647 Green partyhat 114,800,000 1,452,340,733 Purple partyhat 83,100,000 1,233,390,908 Red partyhat 129,400,000 1,738,594,833 White partyhat 183,300,000 2,147,483,644 Yellow partyhat 96,300,000 1,314,553,072 Pumpkin 5,300,000 149,804,919 Easter egg 4,300,000 49,183,614 Blue h'ween mask 12,800,000 101,362,653 Green h'ween mask 10,600,000 82,685,014 Red h'ween mask 17,300,000 132,872,973 Santa hat 14,800,000 115,823,577 Disk of returning 4,700,000 200,971,362 Half full wine jug 31,100,000 348,603,157 Fish mask 29 September 2012 4,555,462 601,926 Christmas tree hat 20 January 2013 2,295,576 12,651,188 Crown of Seasons 23 July 2013 8,307,542 4,044,842 Black Santa hat 20 January 2013 222,967,707 340,890,058 Cloak of Seasons 19 June 2014 7,614,236 27,631,528 Rubber turkey – – 4,140,748 Added item Off-hand rubber turkey 3,590,829 Christmas scythe 72,191,580 Holly wreath 372,492,991 Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 15.3476$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{2,147,483,644}{688,800,000} + \frac{2,147,483,647}{340,100,000} + \frac{1,452,340,733}{114,800,000} + \dots + \frac{340,890,058}{222,967,707} + \frac{27,631,528}{7,614,236} \\ & = 211.91329563 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 211.91329563 - 0 + 4 \\ & = 215.91329563 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 15.3476 \times \frac{215.91329563}{211.91329563} \\ & = 15.6373 \text{ (4 d.p.)} \end{align}$

2015

20 May 2015

Adjusted index: Food Index Adjustment date: 20 May 2015 Affected templates: Template:GE Food Index and Template:GE Food Index/Diff Added item(s): 7 — Bread, Cavefish, Great white shark, Rocktail, Salmon, Saradomin brew (4), Strawberries (5) Removed item(s): 11 — Admiral pie, Garden pie, Kebab, Manta ray, Redberry pie, Roast bird meat, Sea turtle, Stew, Sweetcorn, Ugthanki kebab, Wild pie Items before adjustment: 19 Items after adjustment: 15 Divisor before adjustment: 19.0000 Divisor after adjustment: 8.7619 Item Base date Base price Price on adjustment date Comments Lobster 25 January 2008 175 196 Unchanged Bass 195 225 Tuna 81 163 Swordfish 272 295 Monkfish 233 336 Shark 657 739 Cake 52 91 Chocolate cake 150 421 Ugthanki kebab 887 810 Removed item Kebab 32 276 Sea turtle 1,264 2,690 Manta ray 1,794 1,907 Sweetcorn 135 43 Roast bird meat 22 19 Admiral pie 1,031 497 Wild pie 3,491 985 Redberry pie 381 1,280 Garden pie 657 475 Stew 100 1,102 Bread – – 433 Added item Strawberries (5) 318 Saradomin brew (4) 9,762 Salmon 80 Cavefish 1,256 Rocktail 1,814 Great white shark 912 Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 19.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \text{sum of unchanged ratios} + \text{sum of removed ratios} \\ & = \left (\frac{196}{175} + \frac{225}{195} + \dots + \frac{421}{150} \right ) + \left (\frac{810}{887} + \frac{276}{32} + \dots + \frac{1,102}{100} \right ) \\ & = 42.27255853 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 42.27255853 - \left ( \frac{810}{887} + \frac{276}{32} + \dots + \frac{1,102}{100} \right ) + 7 \\ & = 19.49428715 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 19.0000 \times \frac{42.27255853}{19.49428715} \\ & = 8.7619 \text{ (4 d.p.)} \end{align}$

Price data

Price updating prior to 2012 was done by users either by: checking the in-game prices, or by referring to the Grand Exchange Database. The price data, however, were neither 100% accurate (due to rounding and human errors), nor continuous (due to lack of source for historical data). However, in 2012, Jagex started storing accurate historical data in their database for up to 180 days. This enabled our bots (and users) to obtain continuous accurate data.

Nevertheless, there have been several occasions where the Grand Exchange Database failed:

23–26 March 2012

Update: Unknown edit Affected period: 23–26 March 2012 (4 days) Affected items: All items Comment: Prices from 22 March 2012 shown throughout the affected period. Adjustment method To approximate the prices, the average of the closest known prices (22 March and 27 March) is used. The formula for the k-th missing price is as follows: ${p}_{\text{k}} = {p}_{\text{start}} + \frac{{p}_{\text{end}} - {p}_{\text{start}}}{({d}_{\text{end} \to \text{start}})} \times ({d}_{\text{k} \to \text{start}})$ For example, if the price for Item A is 331 coins on 22 March (P22) and 292 coins on 27 March (P27), then the price for 23 March (P23) would be: $\begin{align} {p}_{\text{23}} &= {p}_{\text{22}} + \frac{{p}_{\text{27}} - {p}_{\text{22}}}{({d}_{\text{27} \to \text{22}})} \times ({d}_{\text{23} \to \text{22}}) \\ \\ &= 331 + \frac{292-331}{5} \times 1 \\ \\ &= 323.2 = 323 \; \text{(rounded to nearest coin)} \end{align}$ And, the price for 24 March (P24) would be: $\begin{align} {p}_{\text{24}} &= {p}_{\text{22}} + \frac{{p}_{\text{27}} - {p}_{\text{22}}}{({d}_{\text{27} \to \text{22}})} \times ({d}_{\text{24} \to \text{22}}) \\ \\ &= 331 + \frac{292-331}{5} \times 2 \\ \\ &= 315.4 = 315 \; \text{(rounded to nearest coin)} \end{align}$ And so on. Thus, using the formula for the missing days, the approximate prices would be: Date > 22 March 23 March 24 March 25 March 26 March 27 March Item A (price) 331 (actual) 323 (calculated) 315 (calculated) 308 (calculated) 300 (calculated) 292 (actual)

6–12 November 2012
Update: Tears of Guthix: Go with the Flow Affected period: 6–12 November 2012 (7 days) Affected items: All items Comment: Prices from 5 November 2012 shown throughout the affected period. Adjustment method: See adjustments made in March 2012.

3–8 April 2013
Update: Dungeoneering Dual Wielding and Charming Imp Affected period: 3–8 April 2013 (6 days) Affected items: All items Comment: Prices from 2 April 2013 shown throughout the affected period. Adjustment method: See adjustments made in March 2012.

17–21 July 2013
Update: Open Beta Update Affected period: 17–21 July 2013 (5 days) Affected items: All items Comment: Prices from 16 July 2013 shown throughout the affected period. On 22 July 2013, Grand Exchange was taken offline for several hours. Adjustment method: See adjustments made in March 2012.

8–14 October 2013
Update: Treevolution - High-Level Trees Affected period: 8–14 October 2013 (7 days) Affected items: All items, including 10 new items added during update Comment: All items had prices shown from 7 October 2013. Prices for 10 new items shown as zero throughout affected period. Adjustment method: See adjustments made in March 2012.

26 November – 1 December 2013
Update: Coinshare, World Map and Tutorial Affected period: 26 November – 1 December 2013 (6 days) Affected items: All items, including 60 new items added during update Comment: Prices from 25 November 2013 shown throughout the affected period. Manual updating by users was also used to obtain in-game prices. Adjustment method: See adjustments made in March 2012.

12 May 2014
Update: Return to Ashdale & Choose Your Path Affected period: 12 May 2014 (1 day) Affected items: All items Comment: All items had prices shown from 11 May 2014. Adjustment method: Average taken of prices from 11 May and 13 May 2014.

12–17 November 2014
Update: Prifddinas - Lost City of the Elves - Part 2 and Treasure Trails Update & Community Tools Affected period: 12–17 November 2014 (6 days) Affected items: 48 items (ItemID 32769 - ItemID 33030) Comment: All affected items had zero instead of their usual prices during affected period. Adjustment method: See adjustments made in March 2012.

Volume data

Since volume data is only available for the 100 most actively traded items on a particular day, there will be occasions where a previously "top 100" item falls out of the "top 100" list. If the item returns to the "top 100" list within a short period, the volume data for the missing days is approximated and added retrospectively.