{"id":926,"date":"2026-11-01T16:39:00","date_gmt":"2026-11-01T15:39:00","guid":{"rendered":"https:\/\/displace-project.org\/blog\/?p=926"},"modified":"2026-10-14T16:51:16","modified_gmt":"2026-10-14T14:51:16","slug":"how-to-show-that-the-modelled-answer-by-displace-beats-the-unmodeled-guess","status":"publish","type":"post","link":"https:\/\/displace-project.org\/blog\/2026\/11\/how-to-show-that-the-modelled-answer-by-displace-beats-the-unmodeled-guess\/","title":{"rendered":"How to show that the modelled answer by DISPLACE beats the unmodeled guess?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Currently working on the following across several seas:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Step 1: Define the counterfactual properly.<\/strong> The &#8220;unmodeled guess&#8221; would be what policymakers would assume is absent in the model, and would be some combination of:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><em>Persistence<\/em>: effort and catches stay roughly where they were<\/li><li><em>Na\u00efve closure arithmetic<\/em>: a closure &#8220;protects&#8221; everything inside its boundary and costs the fleet proportionally to its footprint<\/li><li><em>Proportional redistribution<\/em>: displaced effort spreads uniformly over the remaining grounds<\/li><li><em>Expert judgment<\/em>: what experiential knowledge would say without simulation<\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The &#8220;naive&#8221; baseline assumes fishers don&#8217;t strategically adapt. That is DISPLACE&#8217;s whole point: fleet adaptation most likely occurs in response to area-based management by displacing effort and continuing to fish elsewhere. The comparison shows whether it is real.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Step 2: Use natural experiments where the truth is observable.<\/strong> Real closures happened after the model existed (Baltic cases, Kattegat, Mediterranean fishery-restricted areas). For those, we would retrieve before\/after VMS tracks, logbooks, landings, and fuel data. We would then feed the model only data up to the year before the closure, let it predict the post-closure period, and score it. The unmodeled baseline would make the same prediction for the same period. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Step 3: Score on metrics where behaviour matters most.<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><em>Spatial allocation<\/em>: what fraction of post-closure effort landed in the cells the model assigned it to, versus where persistence\/proportional baselines put it? (use some metrics for that&#8230;)<\/li><li><em>Displacement distance and direction<\/em>: did effort shift to the actual remaining grounds, at roughly the modelled magnitude?<\/li><li><em>Economics<\/em>: revenue and fuel use per fishing fleet segment: compare mean absolute error for each predictor.<\/li><li><em>Probabilistic calibration: run stochastic simulation to capture uncertain<\/em>ties and compare with frequency-type statements&#8230; did the modelled frequencies match realised frequencies? <\/li><\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">DISPLACE doesn&#8217;t need to be right; it needs to be less wrong than the gues<em>s<\/em>. If a retrospective showed, say, that the model beat persistence by 30% on spatial allocation while the naive baseline missed displaced hotspots entirely, that would be a good case to demonstrate that taxpayer money is not misused.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Currently working on the following across several seas: Step 1: Define the counterfactual properly. The &#8220;unmodeled guess&#8221; would be what policymakers would assume is absent in the model, and would be some combination of: Persistence: effort and catches stay roughly where they were Na\u00efve closure arithmetic: a closure &#8220;protects&#8221; everything inside its boundary and costs &hellip; <a href=\"https:\/\/displace-project.org\/blog\/2026\/11\/how-to-show-that-the-modelled-answer-by-displace-beats-the-unmodeled-guess\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;How to show that the modelled answer by DISPLACE beats the unmodeled guess?&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-926","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/posts\/926","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/comments?post=926"}],"version-history":[{"count":9,"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/posts\/926\/revisions"}],"predecessor-version":[{"id":937,"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/posts\/926\/revisions\/937"}],"wp:attachment":[{"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/media?parent=926"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/categories?post=926"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/displace-project.org\/blog\/wp-json\/wp\/v2\/tags?post=926"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}