TOC Project Management An introduction to the Critical Chain method
Characteristics of Projects
Common Complaints in Project Management Usually original due dates are not met There are to many changes Too often resources are not available when needed Necessary things are not available on-time (information, specifications, materials, designs, authorizations, etc.) There are fights about priorities between projects There are budget over-runs There is to much re-work
What is the major cause of their existance? 1) Uncertainty (in processes, in content, in skills, etc.) Significant efforts are focused on reducing uncertainty everywhere. 2) The common practice of managing projects Provides focus on where is important to protect us against uncertainty and change the mode of managing projects.
How do we manage currently our projects? Common practice: The way to ensure that the project will finish on time is to try to make every task finish on time. Reality of projects: High uncertainty, therefore, task times can not be determined, they can Only Be Estimated. Consecuence: The common practice turns task estimations into commitments.
How do we set realistic estimations? REALISTIC ESTIMATION 5 days 5 days 5 days With safety against uncertainty 10 Days 5 days 5 days 12 Days 2 days With safety because of multi-tasking If you don t embed safety in your estimations, your estimations are not realistic!
How much safety is embedded in estimations? Any estimation above 50% embeds safety.
If there s too much safety, how come projects still are not finished on time? Bad Multitasking Parkinson s Law Student syndrome Task integration
Bad Multi-tasking To do tasks Task A Task B Task C 3 days 3 days 3 days Less Productivity What should happend: Task A Task B Task C 3 days 3 days 3 days What might happend: What really happend: A A B C A B 6 days 6 days 6 days B C A 7 days 7 days 7 days C B C
Parkinson s Law Work expands so as to fill the time available for its completion I finished this job early, but I still have two days for the planned delivery, I ll pulish it a little bit more.
Student Syndrome To pospone the start of a job to the last minute I have two weeks to do this homework, plenty of time, so what s the rush!
Integration Delays are transferred to the next task in full, while gains are not transferred at all! A - 10 Days B - 10 Days D C - 10 Days
The CRITICAL CHAIN Method Planning
Step 1. Create the net and cut task estimates in half a) Use task times with a 50% probability to finish on time. A1/20 A2/60 Critical Path: 130 B1/20 B2/40 B3/20 B4/20 B5/30 C1/60 C2/30 A1/10 A2/30 B1/10 B2/20 B3/10B4/10 B5/15 C1/30 C2/15 Available Resources: 1 Green 1 Orange 1 Blue 1 Dark Blue 1 Purple 1 Red 1 Yellow
Step 2. Schedule latest task start Latest start A1/10 A1/10 A2/30 A2/30 B1/10 B2/20 B3/10 B4/10 B5/15 C1/30 C1/30 C2/15 C2/15 Available Resources: 1 Green 1 Orange 1 Blue 1 Dark Blue 1 Purple 1 Red 1 Yellow 0 time Latest start
Step 3. Solve resource contention Blue and orange resources are in conflict A1/10 A2/30 B1/10 B2/20 B3/10 B4/10 B5/15 C1/30 C2/15 A1/10 A1/10 A2/30 A2/30 B1/10 B2/20 B3/10 B4/10 B5/15 C1/30 C1/30 C2/15
Step 4. Determine the Critical Chain Critical Chain The longest chain of dependent tasks considering also resource contention. A1, A2, C2 y B5 A1/10 10 A1/10 A2/30 30 30 B1/10 B2/20 B3/10 B4/10 B5/15 C1/30 30 C2/15 0 time
Step 5. Insert Project Buffer Dealing with uncertainty Add the safety we take out from each crital chain task and put half of it at the end of the project. A1/10 10A2/30 30 B1/10 B2/20 B3/10 B4/10 B5/15 COMPLETI ON DATE C1/30 C2/15 The Project Buffer protects the project completion date against disruptions in the Critical Chain.
Step 6. Insert Feeding Buffers Dealing with uncertainty Where is also the prject vulnerable because of delays or disruptions? COMPLETI ON DATE A1/10 10A2/30 30 B1/10 B2/20 B1/10 B3/10 B2/20 B4/10 B3/10 B4/10 B5/15 C1/30 C1/30 C2/15 The Feeding Buffer protects the Critical Chain from delays elsewhere.
Step 7. Put Resource Buffers RESOURCE BUFFERS A1/10 A2/30 B1/10 B2/20 B3/10 B4/10 B5/15 COMPLETION DATE C1/30 FEEDING BUFFERS C2/15 PROJECT BUFFER The Resource Buffer function is to notify the resources when they are going to be required for worj at the Critical Chain.
A word about Monitoring and Measurement Ingeniería: Terminamos la primer tarea de 2 días de duración, pero todavía nos faltan 4 días para terminar nuestra siguiente tarea Diseño: No hemos tenido oportunidad de iniciar nuestra tarea" Tiempo proyectado de la tarea Consumo del amortiguador 5:Ingeniería 2: AA 2 T.M. 2:Ing. 3:Dsñ. 4: Taller M 2:PIL 6.5: Amort. Proyecto Hoy Tiempo proyectado de las tareas Reporte del Proyecto: CC Completada: 15% AP Consumido: 30%
Proporción entre el consumo del Amortiguador del Proyecto y la porción ya terminada de la Cadena Crítica Consumo del Amortiguador de Proyecto Tarea de la Cadena Crítica Terminada Hoy Reporte del Proyecto: Porcentaje de la Cadena Crítica Completada: 15% Porcentaje del Amort. De Proyecto Consumido: 30%