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Performing a WhatIf Scenario for using Overtime

2 replies [Last post]
Tue, 2016-11-22 20:17
Jorge Cruz
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Joined: 16 Jun 2016
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Hello all,

I´d like to perform a What If scenario for my managers where we could see the possible reduction in our schedule by using Overtime, and second shifts, and also show the Cost Impact of this decision in order to see if this is a good option for the project.Have you done something like this before?

Can you tell me the steps to do this? Or maybe point me in the right direction?
Btw, is a construction project for the automotive industry

Thanks a lot!

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Fri, 2016-11-25 00:25
#1
Rafael Davila
User offline. Last seen 15 hours 8 min ago. Offline
Joined: 1 Mar 2004
Posts: 5229
Groups: Spider Project Team

xxx1 photo xxx1_zps6jw7ig3q.jpg

CALENDARS ARE KEY TO DEFINE WORK TIME FOR EACH SHIFT.

USE RESOURCE PERIODS TO ACCOUNT FOR UNIT COST INCREASE WITH TIME.

rp0034 photo rp0034_zpsbjt2rzjf.jpg

USE OVERTIME SCREEN TO DEFINE COST OF OVERTIME HOURS [SET A CALENDAR TO DEFINE OVERTIME HOURS]

photo xxx5_zpsdrzgoa05.jpg 

photo xxx4_zpsv2jglqxr.jpg

xxx3 photo xxx3_zpsztbtrmxx.jpg

SIMPLE MATH BUT VERY TEDIOUS IF MANUAL

photo OTCALC_zpswlhe7izb.jpg

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Wed, 2016-11-23 14:33
#2
Rafael Davila
User offline. Last seen 15 hours 8 min ago. Offline
Joined: 1 Mar 2004
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Groups: Spider Project Team
  • using Overtime: this shall be easy if using resource hourly cost, resource cost periods and resource overtime.
  • second shifts: this shall be easy if using teams of resources working under different shift calendar, activity calendar shall be the union of all assigned shifts or a 24/7 calendar.
    • each team work independent of each other
    • within a team all resources must work together
    • if all resources must work together that makes a single team
    • if all resources can work independent of each other then each resource is a team of one
    • the work distribution can be distributed in order of team execution [most common] or can be fixed-for-teams
    • team modeling is lacking in many software, in such case a common workaround is to use different activities for each team. This can require trial an error in the most common scenario, when work is done in order of team execution. Say a team 1 works on Monday and Tuesday while team 2 works on Friday and Saturday, if activity can be done by any of the teams within two days if it starts on Monday all work will be done by team 1, if starts on Tuesday some work will be done on Tuesday by team 1 and the remaining by team 2 on Friday.
  • activity duration: if using activity duration driven by resource production rates and volume of work the software shall do the math.
  • cost impact: it is a matter of cost loading your what-if scenarios activities and their resources, overtime will come at a cost, reduced production rates on second shift will also come at a cost, the savings in overhead activities can be modeled if using hammocks, hiring plan to account for idle time can be modeled using activity resource production and consumption.

The following post will provide you with some images might give you an idea on how it can be done, the details will deppend on the software you use.

If your software is not capable of dealing with multiple teams working on a single activity or not capable of driving activity duration using resource production rates you might need to work it around using manual methods.

Easy but very tedious, good luck.

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