{"id":360,"date":"2010-01-21T13:21:07","date_gmt":"2010-01-21T12:21:07","guid":{"rendered":"http:\/\/www.auditsi.eu\/?p=360"},"modified":"2013-12-26T21:55:00","modified_gmt":"2013-12-26T19:55:00","slug":"echantillonnage-de-donnees-selection-aleatoire-de-donnees","status":"publish","type":"post","link":"https:\/\/www.auditsi.eu\/?p=360","title":{"rendered":"Echantillonnage de donn\u00e9es : s\u00e9lection al\u00e9atoire de donn\u00e9es"},"content":{"rendered":"<p style=\"text-align: justify;\"><strong><em><span style=\"text-decoration: underline;\">Int\u00e9r\u00eat d&#8217;une s\u00e9lection al\u00e9atoire<\/span><\/em><\/strong><\/p>\n<p style=\"text-align: justify;\">Le commissaire aux comptes effectue la plupart de ses contr\u00f4les par sondage. La formation d&#8217;un \u00e9chantillon de donn\u00e9es \u00e0 sonder est r\u00e9alis\u00e9e selon diff\u00e9rentes m\u00e9thodes au choix de l&#8217;auditeur (conform\u00e9ment \u00e0 la NEP-530. S\u00e9lection des \u00e9l\u00e9ments \u00e0 contr\u00f4ler). La s\u00e9lection des donn\u00e9es s&#8217;op\u00e8re en fonction :<\/p>\n<ul style=\"text-align: justify;\">\n<li>d&#8217;un seuil de signification,<\/li>\n<li>d&#8217;une m\u00e9thode statistique,<\/li>\n<li>d&#8217;une formule al\u00e9atoire,<\/li>\n<li>de crit\u00e8res plus ou moins subjectifs.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\">Ces diff\u00e9rentes m\u00e9thodes sont utilisables conjointement mais la plupart du temps, l&#8217;\u00e9chantillon est form\u00e9 \u00e0 partir d&#8217;un seuil de signification (par exemple, toutes les donn\u00e9es dont le montant est sup\u00e9rieur \u00e0 100 K\u20ac). L&#8217;utilisation dogmatique de ce crit\u00e8re de s\u00e9lection \u00e9liminera syst\u00e9matiquement toutes les donn\u00e9es inf\u00e9rieures au seuil (alors que pr\u00e9cis\u00e9ment l&#8217;ensemble des membres d&#8217;une population donn\u00e9e m\u00e9rite l&#8217;attention du CAC) et ne r\u00e9pond pas au caract\u00e8re impr\u00e9visible des contr\u00f4les du commissaire aux comptes institu\u00e9 par les NEP (normes d&#8217;exercice professionnel), notamment la NEP-330 intitul\u00e9e &#8220;Proc\u00e9dures\u00a0d&#8217;audit\u00a0mises en oeuvre par le commisaire aux comptes \u00e0 l&#8217;issue de son \u00e9valuation des risques&#8221;.<\/p>\n<p style=\"text-align: justify;\">L&#8217;utilisation du hasard, en compl\u00e9ment d&#8217;autres m\u00e9thodes d&#8217;\u00e9chantillonnage, est tr\u00e8s int\u00e9ressante \u00e0 double titre :<\/p>\n<ul style=\"text-align: justify;\">\n<li>D&#8217;une part, cette m\u00e9thode r\u00e9pond aux prescriptions des NEP sur l&#8217;impr\u00e9visibilit\u00e9 des contr\u00f4les du CAC; dans le cadre de la pr\u00e9vention de la fraude, ce genre de m\u00e9thode introduit un climat d&#8217;ins\u00e9curit\u00e9 pour le fraudeur ou l&#8217;\u00e9ventuel fraudeur, en effet, toutes les transactions sont susceptibles d&#8217;entrer dans le p\u00e9rim\u00e8tre de l&#8217;audit et non pas seulement les plus importantes.<\/li>\n<li>D&#8217;autre part, elle permet d&#8217;\u00e9largir l&#8217;\u00e9ventail de donn\u00e9es audit\u00e9es&#8230; et finalement d&#8217;augmenter la probabilit\u00e9 de d\u00e9tecter erreurs et fraudes, ces derni\u00e8res \u00e9tant d&#8217;ailleurs le plus souvent d\u00e9couvertes par hasard.<\/li>\n<\/ul>\n<p style=\"text-align: justify;\"><strong><em><span style=\"text-decoration: underline;\">R\u00e9alisation d&#8217;un \u00e9chantillonnage al\u00e9atoire \u00e0 l&#8217;aide d&#8217;une requ\u00eate SQL<\/span><\/em><\/strong><\/p>\n<p style=\"text-align: justify;\">L&#8217;exemple qui suit servira d&#8217;illustration au propos pr\u00e9c\u00e9dent. Nous utiliserons un grand livre g\u00e9n\u00e9ral (table ACCESS intitul\u00e9e <em>GL<\/em> comprenant les champs de donn\u00e9es compte, libell\u00e9 (d&#8217;\u00e9criture), journal, d\u00e9bit, cr\u00e9dit et num\u00e9ro de pi\u00e8ce). Il comprend dix-huit mille lignes d&#8217;\u00e9critures et nous souhaitons n&#8217;en retenir al\u00e9atoirement aux fins d&#8217;audit que dix lignes.<\/p>\n<p style=\"text-align: justify;\"><em><span style=\"text-decoration: underline;\">Texte de la requ\u00eate SQL \u00e0 r\u00e9diger :<\/span><\/em><\/p>\n<p style=\"text-align: justify;\">SELECT TOP 10 GL.Compte, GL.Libell\u00e9, GL.D\u00e9bit, GL.Cr\u00e9dit, GL.Journal, GL.Date, GL.Lettrage, GL.Pi\u00e8ce<\/p>\n<p style=\"text-align: justify;\">FROM GL<\/p>\n<p style=\"text-align: justify;\">ORDER BY Rnd(compte);<\/p>\n<p style=\"text-align: justify;\"><em><span style=\"text-decoration: underline;\">Explication :<\/span><\/em><\/p>\n<p style=\"text-align: justify;\">L&#8217;\u00e9chantillonnage tourne autour des deux fonctions suivantes :<\/p>\n<ul>\n<li style=\"text-align: justify;\"><em>\u00abORDER BY Rnd(compte)\u00bb <\/em>trie les lignes al\u00e9atoirement par le champ <em>\u00abcompte\u00bb<\/em>,<\/li>\n<li style=\"text-align: justify;\"><em>\u00abTOP 10\u00bb<\/em> signifie que l&#8217;on ne s\u00e9lectionne que les dix premi\u00e8res lignes du r\u00e9sultat de la requ\u00eate.<\/li>\n<\/ul>\n<p><em><span style=\"text-decoration: underline;\">R\u00e9sultat obtenu :<\/span><\/em><\/p>\n<p><a href=\"https:\/\/www.auditsi.eu\/wp-content\/uploads\/2010\/01\/ReqS\u00e9lectional\u00e9atoire.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-1043\" title=\"ReqS\u00e9lectional\u00e9atoire\" alt=\"\" src=\"https:\/\/www.auditsi.eu\/wp-content\/uploads\/2010\/01\/ReqS\u00e9lectional\u00e9atoire.jpg\" width=\"568\" height=\"242\" srcset=\"https:\/\/www.auditsi.eu\/wp-content\/uploads\/2010\/01\/ReqS\u00e9lectional\u00e9atoire.jpg 568w, https:\/\/www.auditsi.eu\/wp-content\/uploads\/2010\/01\/ReqS\u00e9lectional\u00e9atoire-300x127.jpg 300w, https:\/\/www.auditsi.eu\/wp-content\/uploads\/2010\/01\/ReqS\u00e9lectional\u00e9atoire-1x1.jpg 1w\" sizes=\"auto, (max-width: 568px) 100vw, 568px\" \/><\/a><\/p>\n<p>Bien entendu, chaque ex\u00e9cution de la requ\u00eate donne un r\u00e9sultat diff\u00e9rent.<\/p>\n<div style=\"padding-bottom:20px; padding-top:10px;\" class=\"hupso-share-buttons\"><!-- Hupso Share Buttons - https:\/\/www.hupso.com\/share\/ --><a class=\"hupso_counters\" href=\"https:\/\/www.hupso.com\/share\/\"><img decoding=\"async\" src=\"https:\/\/static.hupso.com\/share\/buttons\/lang\/fr\/share-small.png\" style=\"border:0px; padding-top:2px; float:left;\" alt=\"Share Button\"\/><\/a><script type=\"text\/javascript\">var hupso_services_c=new Array(\"twitter\",\"facebook_like\",\"facebook_send\",\"email\",\"print\",\"linkedin\");var hupso_counters_lang = \"fr_FR\";var hupso_image_folder_url = \"\";var hupso_twitter_via=\"BenoitRiviere14\";var hupso_url_c=\"\";var hupso_title_c=\"Echantillonnage%20de%20donn%C3%A9es%20%3A%20s%C3%A9lection%20al%C3%A9atoire%20de%20donn%C3%A9es\";<\/script><script type=\"text\/javascript\" src=\"https:\/\/static.hupso.com\/share\/js\/counters.js\"><\/script><!-- Hupso Share Buttons --><\/div>","protected":false},"excerpt":{"rendered":"<p>Int\u00e9r\u00eat d&#8217;une s\u00e9lection al\u00e9atoire Le commissaire aux comptes effectue la plupart de ses contr\u00f4les par sondage. La formation d&#8217;un \u00e9chantillon de donn\u00e9es \u00e0 sonder est r\u00e9alis\u00e9e selon diff\u00e9rentes m\u00e9thodes au choix de l&#8217;auditeur (conform\u00e9ment \u00e0 la NEP-530. S\u00e9lection des \u00e9l\u00e9ments \u00e0 contr\u00f4ler). La s\u00e9lection des donn\u00e9es s&#8217;op\u00e8re en fonction : d&#8217;un seuil de signification, d&#8217;une &#8230;<\/p>\n<p><a href=\"https:\/\/www.auditsi.eu\/?p=360\" class=\"more-link\">Continue reading &lsquo;Echantillonnage de donn\u00e9es : s\u00e9lection al\u00e9atoire de donn\u00e9es&rsquo; &raquo;<\/a><\/p>\n<div style=\"padding-bottom:20px; padding-top:10px;\" class=\"hupso-share-buttons\"><!-- Hupso Share Buttons - https:\/\/www.hupso.com\/share\/ --><a class=\"hupso_counters\" href=\"https:\/\/www.hupso.com\/share\/\"><img src=\"https:\/\/static.hupso.com\/share\/buttons\/lang\/fr\/share-small.png\" style=\"border:0px; padding-top:2px; float:left;\" alt=\"Share Button\"\/><\/a><script type=\"text\/javascript\">var hupso_services_c=new Array(\"twitter\",\"facebook_like\",\"facebook_send\",\"email\",\"print\",\"linkedin\");var hupso_counters_lang = \"fr_FR\";var hupso_image_folder_url = \"\";var hupso_twitter_via=\"BenoitRiviere14\";var hupso_url_c=\"\";var hupso_title_c=\"Echantillonnage%20de%20donn%C3%A9es%20%3A%20s%C3%A9lection%20al%C3%A9atoire%20de%20donn%C3%A9es\";<\/script><script type=\"text\/javascript\" src=\"https:\/\/static.hupso.com\/share\/js\/counters.js\"><\/script><!-- Hupso Share Buttons --><\/div>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"ngg_post_thumbnail":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[50,39,40,4,21,282,470],"tags":[60,128,1631,132,17,127,90,52,1621,131,129,20,1623,394,395,396,301,26,57,130,133],"class_list":["post-360","post","type-post","status-publish","format-standard","hentry","category-audit-de-donnees","category-cas-pratiques","category-controle-des-comptes","category-fraude","category-nep","category-sql","category-techniques-daudit","tag-access","tag-aleatoire","tag-cas-pratiques","tag-climat-dinsecurite","tag-demarche-daudit","tag-echantillonnage","tag-erreurs","tag-exploitation-des-donnees","tag-fraude","tag-fraudeur","tag-hasard","tag-imprevisibilite","tag-nep","tag-nep-240","tag-nep-330","tag-nep-530","tag-normes-dexercice-professionnel","tag-prevention-de-la-fraude","tag-requete-sql","tag-seuil-de-signification","tag-transaction"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_likes_enabled":false,"_links":{"self":[{"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=\/wp\/v2\/posts\/360","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=360"}],"version-history":[{"count":2,"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=\/wp\/v2\/posts\/360\/revisions"}],"predecessor-version":[{"id":4341,"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=\/wp\/v2\/posts\/360\/revisions\/4341"}],"wp:attachment":[{"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=360"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=360"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.auditsi.eu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=360"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}