In Pursuit of Reliable Schedules
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PMA’s Core Traits of a Reliable Schedule and NetPoint Schedule Analytics represent our contributions to date, aimed at improving plan and schedule quality in the AEC industry. Factors contributing to the state of scheduling today include; tension of current Total Float ownership principles, complex projects and sophisticated scheduling tools, and that greater activity detail leads to more accurate schedules.
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In Pursuit of Reliable Schedules
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- 3. What Factors Contribute to the State of Scheduling Today? 3 • Incite adversarial relationships • Incentivize withholding of information • Commandeer a collaborative tool for less value adding purposes • In the hands of inexperienced and/or poorly trained schedulers • Insufficient emphasis on or understanding of best practices • Stakeholders and SME’s are disenfranchised from the planning process Complex projects & sophisticated scheduling tools: 1 Presupposition that greater activity detail leads to more accurate schedules Ever‐present tension of current Total Float ownership principles, which: 2 3
- 5. CPM Scheduling SMEs GPM Planning/Scheduling SMEs February 2014 Core Traits of a Reliable Schedule Gui Ponce de Leon, PhD, PE, PMP, LEED AP Eric D. Lowther, PMP, LEED AP Gary H. Jentzen, PE, JD, LEED AP Don J. Fredlund, PMP John D. Sheridan, LEED AP Gerald P. Klanac Bruce Stephan, PE, JD, PMP Rich P. Martone Herschel Baxi, PMP, LEED AP Timothy D. Mather, PMP Dax Ponce de Leon, LEED AP BD+C, PMP Dennis Lucey Noel Alvarez, PMP, LEED AP Ken A. VanderJagt, PE, PMP Wayne E. Beauregard, PSP Eduardo A. Nazario Scott E. Worth, PMP, LEED AP David J. Weber Angel F. Arvelo, LEED AP Angel R. Ripepi Kaveh Dabiran, LEED AP Purvasha V. Patel, PE Vivek Puri, PhD Contributing Authors Darrel Field, PE, LEED AP Philip J. Spittler, PMP John Zann, PE, PSP, LEED AP © 2013, 2014 PMA Consultants, LLC
- 7. Must Be Aligned With Contract: Use of Core Traits of a Reliable Schedule must be coordinated with provisions of the contract, and requires the application of professional judgment based on adequate experience and knowledge of construction schedules, including the review of schedules. As written, the 20‐Trait Protocol is geared to design‐bid‐build contracts for major projects and focuses on the period from contract notice to proceed through closeout » A major project is US $250M‐$1B » construction (through closeout) spanning 27‐40 months The 20‐Trait Protocol is scalable to both smaller projects and to mega projects (construction value exceeding US$1B)3 and project delivery method Scope Caveats 7
- 8. 1. 20 Traits advocates for Level 2 schedules as the “Contract Schedule” supported by Level 3 Schedules 2. The level 2 schedule is traceable to, the level 3 schedule 3. The schedule expressly accounts for normal weather and, when updated, incorporates the impact of actual weather. 4. Because the schedule includes and discloses contingency, realistic early completion schedules are a new normal. Novel Approach to Scheduling 8
- 9. 5. Contingency or schedule margin supporting the targeted probability of completion is developed through risk assessment. 6. Critical path float ownership theory that reserves a reasonable level of schedule margin solely for the contractor’s use is endorsed over the rule “the project owns the float.” 7. Relative to a risk‐assessed, revised baseline, the likely impact on the required completion date from a delay on or off the critical path can be determined through an approach that compares the probability of completing on time for the impacted, revised baseline schedule with the probability of completing on time for a but‐for schedule scenario that collapses the delay. Novel Approach to Scheduling 9
- 10. INTRODUCTION 10
- 11. Comprehensive Credible Well Constructed Controlled The Four Corners of Reliable Schedules 1. It is authored, understood and followed by key stakeholders – Not just one savvy scheduler? 2. Is free from technical deficiencies? 3. It is a credible predictor of schedule performance? What are the characteristics of a reliable schedule? 11
- 12. The Schedule Is Comprehensive The Schedule Is Credible The Schedule Is Well Constructed The Schedule Is Controlled A1 Aligned B1 Predictive C1 Hierarchical D1 Statused A2 Complete B2 Risked C2 Phased D2 Weathered A3 Conforming B3 Weather‐Fit C3 Logical D3 Re‐baselined A4 Formulaic B4 Resource‐Flowing C4 Connected D4 Forensic A5 Resourced B5 Flexible C5 Calendar‐Fit D5 Trended 20 Core Traits of a Reliable Schedule © 2013, 2014 PMA Consultants, LLC 12
- 13. Best Practices re: Comprehensive Schedules © 2013, 2014 PMA Consultants, LLC 13 A. COMPREHENSIVE Schedule Deliverable Core Traits 20‐Trait Protocol Essential Statement Selected Supporting Best Practices & Indicators of Schedule Reliability A1 Aligned The schedule portrays a viable plan that aligns with the contractor planning basis and the procurement approach and that takes into account subcontractors’ schedules; the schedule is supported by a narrative The contract schedule is signed off ▪The narrative documents involvement in the developmentof the schedule by contractor managementand supervision personnel and by subcontractors with 2% or more of the contract and/or work on the critical path A2 Complete The entire work, including specified responsibilities of the owner, owner’s consultants and third parties, is captured by and discernible from the activities, logic ties, milestones, and benchmarks Activities are developedusing the WBS context inherent in the drawings and specifications and/or BIM database ▪Every WBS element has at least one associated activity▪ Useful codes are provided to organize, filter, and roll up level 3 schedule activities A3 Conforming The schedule substantiates compliance with contract dates, specified sequences and other contract conditions governing schedule performance; the initial schedule data date is the contract start date NOprogress,delay, or contract changes whatsoever are reflected or incorporated in an initial schedule ▪Every contractual finish milestonefalls on or beforethespecified date ▪The schedule incorporatescontractual constraints and activity/logic sequences A4 Formulaic Physical work activity durations are largely formulaicand align with the schedule level; duration formulae feature production rates, approach to normal adverse weather, working conditions, and working schedules At a minimum, critical/near‐critical physical work activities have formulaic durations ▪Delivery activity durations are based on POs, to the extent existing ▪Over 80% of level 3 schedule activities generally last 2–6 weeks (6weeks‐6 months for level 2) A5 Resourced The schedule reflects the resources needed, their availability to support the rate of progress, and known limits; availabilityof resources to support the rate of progress is confirmed initially and periodically Crew loading is consistent with the formulae used to determine durations ▪Resource leveling trials are undertaken to confirm that resource histograms can be leveled within headcount limits ▪Physical work activities are loaded with resources
- 14. Best Practices re: Credible Schedules © 2013, 2014 PMA Consultants, LLC 14 B. CREDIBLE Schedule Deliverable Core Traits 20‐Trait Protocol Essential Statement Selected Supporting Best Practices & Indicators of Schedule Reliability B1 Predictive The schedule establishesvalid critical/near‐critical paths; in the initial schedule, the critical path has total float ≥ 0; the baseline, if not risk assessed, reserves 4%‐8% of the length of the critical path as contingency The critical path comprises high‐effort physical work,deliveries that drive the physical work, and commissioning ▪Owner activities are justified and reasonably tied; durations are as specified orotherwise reasonable ▪Soft logic ties & resource‐flow logic ties are justified B2 Risked Using risk assessment, the schedule is established with schedule margin sufficientto support the targeted probability threshold; schedule margin that supports a reasonable probability threshold is contractor float Risk analysis models duration variability and other contractor risks▪ Contingencies for risks that may occur and that are added to durations are removed in risk analysis ▪Mitigation is investigated if the analysis does not support the targeted probability threshold B3 Weather‐Fit The schedule correctly integrates normal adverse weather according to the specifications/best practices; weather planning is based on the most representative pre‐contract record of weather conditions for the site The narrative describes the approach to normal weather ▪Normal weather reflects the reasonably expected mean frequency for each month ▪Duration impacts from production loss due to weather are based on an analysis of the effect of temperature on productivity B4 Resource‐ Flowing Resource‐flow logic ties portray crew movements, equipment logistics/reuse work flow, and material reuse workflow; resource‐flow logic ties are devised by the planner vs. generated by the software Planner‐devised resource‐flow logic ties are used judiciouslyand explained ▪Crew‐flow or similar charts are provided for repeating activities ▪Resource‐flowlogic ties on critical/near‐critical paths are itemized and supported, including contingent measures B5 Flexible Level 3 schedule flexibility right of the data date is adequate for mitigatingdelay/floatingand for resource leveling; total float (CPM schedules) or gap index and float performance index (GPM) are trended CPM schedules: mean total float is trended;FloatTrend Charts plot the changes for the 0, 5th, 10th, & 50th total floatpercentiles ▪GPM schedules: base‐caseschedulesfor calculating gap indexinclude the Rev. 0, a prior update,and arevised schedule
- 15. Best Practices re: Well‐Constructed Schedules © 2013, 2014 PMA Consultants, LLC 15 C. WELLCONSTRUCTED Schedule Deliverable Core Traits 20‐Trait Protocol Essential Statement Selected Supporting Best Practices & Indicators of Schedule Reliability C1 Hierarchical The baselineis developed as alevel 2 schedule that serves as the basis for, and remainstraceable to, the level 3 schedule; milestones with credible timeframesare used to enhance vertical traceability Contract dates and overarching control points are modeled through benchmarks or constrained milestones ▪ Milestone + benchmark count equals 1%‐2% of total activities for the level 3 schedule ▪Hierarchical activity ID codes, if used, enhance vertical traceability C2 Phased Construction phases from siteworkthrough closeout align with the planning basis; phase durations (e.g., earthwork, substructure, shell, interiors, rough‐in, finishes,and commissioning) are benchmarked Construction phase hammocks are established; their durations relative to the length of the critical path are monitored ▪Critical path total float is allocated to phases through benchmarks ▪Commodity curves, if provided, are reasonably phased relative to each other C3 Logical FS logic is favored; constraints, FS lags/leads,& no‐lag SS & FF logic are used judiciously andarejustified when used; constraints, FS lags & leads & no‐lag SS & FF logic are documented in the schedule or narrative FS logic ≥ 80% ▪Constraints ≤ 2% of total activities ▪Redundant links are identified ▪Where constraints cause critical path breaks, the true critical path is revealed through the longest path algorithm ▪The software is used to identify redundant links C4 Connected Every activity has at least one FS or SS predecessor and one FS or FF successor; paired SS/FF logic is used judiciously; GPM planned dates or SNE dates are used to model logic ties external to the schedule CPM schedules: open ends + dangling ends ≤ 1% of the activity count (≤ ½% in GPM) ▪Ladders are used judiciously or broken into their constituent FS‐linked activities ▪Level 3 schedule logic index is 1.5‐2.5 ▪ Level 2 schedule logic index is 1.25‐1.75 C5 Calendar‐Fit Calendars reflect the planning basis, the working schedule, and other limiting factors; wheremultiple calendars cause critical path breaks, the true critical path is identified through the longest‐path algorithm Multiple calendars are used judiciously and minimized for crew‐loaded activities ▪Overtime and shift calendars are compatible with the planning basis and schedule recovery ▪Delivery activity durations are based on the defaultcalendar
- 16. Best Practices re: Controlled Schedules © 2013, 2014 PMA Consultants, LLC 16 D.CONTROLLED Schedule Deliverable Core Traits 20‐Trait Protocol Essential Statement Selected Supporting Best Practices & Indicators of Schedule Reliability D1 Statused The schedule is accurately statusedusing reliable, documented protocols; imminent level 3 schedule activities (e.g., scheduled 1‐2 months after the data date) are resource‐leveled In‐progress activities are statusedbased on remaining duration vs. percent complete ▪At a minimum, out‐of‐sequence progress for critical/near‐ critical activities is repaired to reflect logical flow ▪Actual dates for critical/near‐critical activities are accurate to the day +/‐1 D2 Weathered The schedule is used to evaluate weather delay/gain originating from actual weather conditions in the prior month; consistent methodologies are applied to determine actual and normal adverse weather Adverse weather schedule analysis considers work stoppages and production loss (in the latter case,when crews continue working) ▪ Production loss when crews work through adverse weather is based on an analysisof the effect of temperatureon productivity D3 Re‐baselined The schedule is re‐baselinedto reflect replanning, time impacts, and schedule recovery; a revised schedule is risk assessed to determine whether the risk analysissupports the initially targeted probability of completion A revised baseline attaches a narrative and is duly signed off ▪Variances for critical/near‐critical activities and milestones are evaluated ▪Every non‐progress revision is documented ▪The impact of schedule recovery on durations is properly recognized D4 Forensic In a statusedor revised GPM schedule,the as‐built critical path is algorithmically identified left of the data date (from the project start event to the data date) The current as‐built critical path is calculated by the software and connects to the critical path right of the data date ▪Every activity on the as‐built critical path has forensic drift = 0 and forensic float = critical path float right of the data date D5 Trended Activity rate of completion is sufficient so that the scope of remaining activities is congruent with an achievablerate of progress; schedule indices are trended and evaluated for the Level 3 schedule Schedule margin is trended as % of the remaining length of the critical path ▪Execution, resource, &duration indices are trended for the level 3 Rev. 0 early & late schedules and the current early schedule ▪Actual and formulaic production rates are compared
- 19. Topics Selected for Discussion A Reliable Schedule Standards B Metrics Analysis Supports Standards C NetPoint v5.2 Schedule Analytics D Schedule IQ™ 19
- 22. Traits in green have elements in common with a GAO best practice for project schedules Reliable Construction Schedules per the 20‐Trait Protocol The Schedule Is Comprehensive The Schedule Is Credible The Schedule Is Well Constructed The Schedule Is Controlled A1 Aligned B1 Predictive C1 Hierarchical D1 Statused A2 Complete B2 Risked C2 Phased D2 Weathered A3 Conforming B3 Weather Fit C3 Logical D3 Re‐ baselined A4 Formulaic B4 Resource Flowing C4 Connected D4 Forensic A5 Resourced B5 Flexible C5 Calendar‐Fit D5 Trended 22
- 24. Metrics Analysis Supports Standards Examples: • Number of stakeholders named as schedule signators • Percent of activities without a predecessor • Percent of activities on the critical path • Critical path total float as a ratio to project length • Mean and median total float • # of milestones + # of benchmarks as a ratio to # of activities What Are Schedule Metrics? Metrics are measurements of information about a schedule with respect to important features 24
- 28. • Data metrics, i.e., varying activity counts, logic counts, and other relevant schedule counts • Up to 45 metrics are analyzed and combined into Schedule IQ™, a reliability score for baselines and updates • Weather enabling protocol that uses weather calendars to calculate “weathered start dates” and “weathered finish dates” • Comparative analysis pinpoints changes between a current baseline or an update against a prior baseline, update, or target NetPoint v5.2 Schedule Analytics Measure, score, validate, and enable schedule reliability through an interactive, flexible application of the 20‐Trait Protocol using the comprehensive, credible, well‐constructed, and controlled framework 28
- 29. NetPoint v5.2 Schedule Analytics Framework The Schedule Is: NetPoint Schedule Metrics NetPoint Reliability Indicators Captures 14‐Point Assessment Metric Number Comprehensive Over 200 10 8 & 10 Credible 5 6, 7 & 13 Well Constructed 10 1, 2, 3, 4 & 5 Controlled 5 9, 11, 12 & 14 A 30‐Point Assessment 29
- 31. Normative activity duration ranges (major projects, per the 20‐ Trait Protocol and PMI’s CPM Scheduling for Construction) Example Physical Work Activity Duration Granularity 20-Trait Protocol DCMA Deltek Fuse PMI CPM Scheduling Level 1 2 ‐ 12 months ≤ 44 days ≤ 10% of project duration 3‐12 months Level 2 5% ‐ 15% of project duration, generally 6 weeks ‐ 6 months 2‐6 months Level 3 1% ‐ 3% of project duration, generally 2 ‐ 6 weeks 2‐6 weeks Level 4 ≤ 1% of project duration, generally ≤ 2 weeks 2‐4 weeks 31
- 36. SCHEDULE IQ™
- 38. Schedule IQ™ Inner Workings─Un‐progressed Baselines Schedule IQ™ operates as a series of 39 independent reliability indicator tests, each test yielding a score that contributes to the total score (100) Un‐progressed Baseline # of Independent Tests Contribution to IQ Score Comprehensive 12 34% Credible 11 25% Well Constructed 15 38% Controlled 1 3% 38
- 39. Schedule IQ™ Inner Workings─Progressed Baselines The number of independent reliability indicator tests increases to 45 for progressed baselines; the contribution to IQ score changes accordingly Progressed Baseline # of Independent Tests Contribution to IQ Score Comprehensive 12 31% Credible 11 23% Well Constructed 15 34% Controlled 7 12% 39
- 42. SUMMARY
- 45. APPENDIX B─NetPoint v5.2 Float‐Related Metrics Activities Total Float Link Gap Metrics Other Float‐Related Metrics With negative total float Critical path index With zero gap Float performance index Critical Critical path total float With positive gap Gap index Near‐critical Mean With negative gap Activities with total float ≤ 5th percentile With positive drift Mean non‐critical With gap ≥ 20 periods Activities with total float ≤ 10th percentile With total float = drift Median With extreme gap Activities with total float ≤ 50th percentile With extreme total float 5th percentile With actualized gap Mean free float With positive free float 10th percentile With actualized negative gap Mean non‐critical free float Forensic critical 80th percentile (Extreme total float) FF links with gap = 0 Gap sum embedded in the critical path Forensic near‐critical Total float index SS links with gap = 0 Gap sum embedded in the as‐built critical path 45