In the example below, the FS relationship between Activity B (B) and Activity H (H) is redundant because an existing inferred relationship between these 2 activities already exists through B->C->D->E->F->G->H. Since B and F are not directly related, then the relationship B->F is said to be \u201cRedundant\u201d since intermediate activities exists between each activity which are along the same logic path. <\/p>\n\n\n\n
Since the relationship B->H is redundant, then this relationship can be safely deleted and will not affect any dates or Total Float values of any activity within the CPM network. Redundant relationships are easily detectable when a logic path is neatly grouped so that activities of the same logic path are sorted by start date. In the example below, activities B thru G are group in the same logic path and are sorted by Start date. The 3 redundant relationships are clearly shown (B->H; C-> E; and E->G) by the dotted relationship lines and therefore can be safely deleted.<\/p>\n\n\n\n Even though a redundant relationship exists, it doesn\u2019t necessarily mean that the relationship should be deleted. A Scheduler may decide to intentionally retain a redundant relationship in the CPM Network. For example, the redundant relationship may represent a secondary \u201cfallback\u201d relationship in case the current driving relationship is not sustainable. For example, in the illustration above, suppose the current driving predecessor (D) to Activity E is no longer valid. Then, by removing the relationship, D->E, then the new driving predecessor to E will be C. If the redundant relationship, C->E had been previously removed, then when the relationship D->E is removed, E will revert back to the Data Date when the schedule is recalculated.<\/p>\n\n\n\n For this reason, using redundant relationship removal algorithms is generally not recommended. Furthermore, and unfortunately, when it comes to P6, all relationships (other than the relationship type) are the same. There is no direct way to differentiate \u201csoft\u201d relationships from \u201chard\u201d relationships; or \u201cprimary\u201d relationships from \u201csecondary\u201d relationships; or \u201cphysical\u201d relationships from \u201ccrew\u201d relationships. <\/p>\n\n\n\n Redundant relationship removal algorithms generally remove relationships regardless of their priority or classification. Therefore, the recommended method for removal of relationships is by individual consideration and inspection.<\/p>\n\n\n\n A Duplicate Relationship<\/strong> is defined as: an additional logic relationship between 2 activities that are directly\nrelated to each other.<\/em> <\/p>\n\n\n\n Duplicate relationships can be\nclassified into 2 types.<\/p>\n\n\n\n In the illustration above, the first\ntype (Type 1) of Duplicate Relationship occurs when a SS\/FF relationship pair is\nused. Typically, a lag value (typically greater than 0) is\nincluded in both relationship. This relationship technique is often used in\nsummary level type schedules where the activity detail is not totally defined. Since\nthe preferred technique in CPM networks is to allow only 1 relationship between\nany 2 activities, this usage is not recommended for detailed or production level\nschedules.<\/p>\n\n\n\n The second type (Type 2) of\nDuplicate Relationship occurs when the relationship pair is not of the SS\/FF\ntype. These duplicate pairs often occur when the \u201cLink Relationship\u201d option is\ninadvertently used a second time (or more) spanning activities that are already\nrelated. In most cases, the non-driving relationship is the relationship that\nshould be deleted. Therefore, for K->L, the FF duplicate relationship can be\nsafely deleted.<\/p>\n\n\n\n A subset of the Type 2 Duplicate Relationship is the \u201cMultiple Instances\u201d variety where more than 2 Duplicate Relationships exist between 2 activities. An example of this, as shown below, displays the relationships between M->N where every possible logic relationship exists between the 2 activities. <\/p>\n\n\n\n In the Successors relationship\nwindow above, since the Driving relationship is FS, then all other listed\nrelationships can be safely deleted.<\/p>\n\n\n\n Z\u00fcmmer\u2019s Analysis Report #39 \u2013 \u201cDuplicate Logic Relationships\u201d shown below, lists all duplicate logic relationships in the selected Project.<\/p>\n\n\n\n This report groups duplicate logic\nrelationships separated by a heavy horizontal line. In the example above, the\nduplicate logic relationship between M->N displays the Type 2 variety with all\n4 assigned relationships. For this condition, the FF, SF and SS relationships\ncan be safely deleted. <\/p>\n\n\n\n The next group, between K->L,\ndisplays the Type 2 variety with the FF\/FS pair. For this condition, the FF\nrelationship can be safely deleted.<\/p>\n\n\n\n The last group, between I->J, displays the Type 1 variety with the SS\/FF pair. Here, the I->J relationship contains a lag of 5 days for both SS and FF relationships. If Activities I & J are part of a detail production level schedule, then breaking down the scope into more detailed activities may be necessary to eliminate the duplicate logic condition. <\/p>\n\n\n\n Copyright \u00a92020 FoxQuest Systems, Inc. – All Rights Reserved<\/p>\n","protected":false},"excerpt":{"rendered":" Defining Relationship Terms.<\/p>\n","protected":false},"author":2,"featured_media":1682,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","om_disable_all_campaigns":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[12],"tags":[],"class_list":["post-1681","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tips"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.foxquestsystems.net\/foxblog\/wp-content\/uploads\/2020\/02\/R00-Redundant-vs-Duplicate-Logic-Feature-Image.jpg?fit=822%2C453&ssl=1","_links":{"self":[{"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/posts\/1681","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/comments?post=1681"}],"version-history":[{"count":5,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/posts\/1681\/revisions"}],"predecessor-version":[{"id":1696,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/posts\/1681\/revisions\/1696"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/media\/1682"}],"wp:attachment":[{"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/media?parent=1681"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/categories?post=1681"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.foxquestsystems.net\/foxblog\/wp-json\/wp\/v2\/tags?post=1681"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/i0.wp.com\/www.foxquestsystems.net\/foxblog\/wp-content\/uploads\/2020\/02\/R02-Redundant-vs-Duplicate-Logic3.jpg?resize=840%2C357&ssl=1\")
<\/figure>\n\n\n\n
<\/strong><\/p>\n\n\n\n![\"\"](\"https:\/\/i0.wp.com\/www.foxquestsystems.net\/foxblog\/wp-content\/uploads\/2020\/02\/R04-Duplicate-Logic-Relationships-Multiple-Instances-Successors-Only.jpg?resize=628%2C199&ssl=1\")
<\/figure>\n\n\n\n![\"\"](\"https:\/\/i0.wp.com\/www.foxquestsystems.net\/foxblog\/wp-content\/uploads\/2020\/02\/R03-39-Duplicate-Logic-Relationships-Report.jpg?resize=840%2C544&ssl=1\")
<\/figure>\n\n\n\n