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How is duration calculated?

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Level 5
Hi All- this seems like a silly question- but my PM's are obsessing about it- how is duration calculated? I know it depends on the task settings- let's assume it's a calculated assignment, and as sson as possible (we're still learning how to leverage all these settings) i.e- task duration 10/1-10/2 (in WF is 1 day, but in our previous system- counted as 2 days. task duration monday through friday (in WF is 4 days, but in our previous system counted as 5 days. The rational I come up with is- Monday to Tuesday is 1 day, Tuesday to Wednesday is 1 day- and so on. Is that the correct way to explain it to the pm's? And also- if the duration is SAME day- do you all put 0 days to make sure the dates stay on the same day? i.e- task starts 10/1 and finishes 10/1- duration = 0 days? or do you put .5 days? Part two: if we have a project- that isn't really going to leverage predecessors, so they're bascially going to hard code the dates- what are the best settings for the task? i.e- duration type and constraint type? thanks in advance for any insight! Karen tks Karen
9 Replies

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Level 10
Hi Karen Here are some considerations: 1) When you have resources assigned and are using Calculated Assignment, WorkFront factors in the Time Off of the resources. If a user is assigned to a task, and that person has time off scheduled during the active period of the task, WorkFront will push out the duration of the task by the number of days being taken off. https://support.workfront.com/hc/en-us/articles/216723348-Personal-Time 2) You have to look at the calendar assigned: a. WorkFront uses the calendar assigned to a user, if the user has one assigned; b. If the user doesn’t have one assigned, WorkFront uses the calendar assigned to the project; 3) We had a lot of occasions where PMs couldn’t figure out why the dates were working out the way they were. The root cause was because of time off or a holiday (schedule exception) in the calendar of the user or the project; 4) Using Calculated Assignment, you have to provide the task duration and the planned hours for the task, and WorkFront calculates the assignment for each resource. Using Calculated Assignment, Duration is NOT calculated. https://support.workfront.com/hc/en-us/articles/217186267-Calculated-Assignment 5) If you want WorkFront to calculate Duration, you need to use Effort Driven. You provide the planned hours on the tasks assigned, and WorkFront calculates the Planned Duration for you. Effort driven means the duration of the task is driven by the effort assigned to resources https://support.workfront.com/hc/en-us/articles/216636758-Effort-Driven I encourage PMs to use a task constraint of Simple. While there are times when it is convenient to let Workfront calculate things for you, we found using Effort Driven caused a lot of shifting of the dates unexpectedly (because the PM didn’t understand what Effort Driven did). We have a resource manager that manages her resources using percentages allocated to a task, so she uses Calculated Assignment a lot. That’s fine. She understands how it works and it fits with how she mentally manages people. She is the exception. Since we started using Simple, and asking PMs to work out the durations and planned hours, we’ve had far less trouble. If your PMs are going to use FIXED DATES, they may as well use Excel. It’s easier. ☺ We do not allow PMs to fix dates in a plan with one exception - when there is an event that is beyond the control of the project team. For example, if a contract expires on a particular date, we’ll fix that date in a plan. If a client has a go live date that we have to support, we fix that date in our plan. Otherwise, we take the view that a project plan is an elastic model of the future. When you fix dates, you remove that elasticity. In other words, when something changes on one task, a plan full of Fixed Dates does not adjust and adapt to that change. The impact of the change is only visible in the task that changed, and the PM has no indication of the potential impact to any other aspect of the project. I consider that a highly risky way of forecasting work. Eliminating the ability to see the impact of a change on the plan introduces a whole host of possible problems. Been there, done that, got the t-shirt and the tattoo. We don’t allow fixed dates. If your PMs are going to fix dates, FIXED DATES is a task constraint type (like ASAP, ALAP, MUST FINISH ON, MUST START ON, and so on). No need to worry about the other settings. https://support.workfront.com/hc/en-us/articles/217297147-Task-Constraint-Overview Btw, we don’t allow MUST START ON or MUST FINISH on, with certain special (and rate) exceptions. Those also remove the elasticity of a plan. Let’s take a look at Duration Types: https://support.workfront.com/hc/en-us/articles/216636598-Duration-Type-Overview If you want WorkFront to take the duration and calculate the planned of work for each person assigned, use a Duration Type of Calculated Assignment. It assumes every resource is assigned at 100%. So if you have a duration of 8 hours, and one resource assigned, it will yield planned hours of 8 labor hours. If you add another resource to the task, it will assume the resource is assigned at 100% for 8 hours of duration, so it will add another 8 hours to the planned hours, for a total of 16 planned hours. If you want WorkFront to take the duration and overall planned hours and assign the planned hours to the resources, use Calculated Assignment. That means if you have a duration of 10 days and planned hours of 50 hours, and one resource assigned, it will give that resource 5 hours per work day. If you add another resource to the plan, the duration and planned hours stay the same, but each resource will get half of the planned hours for the duration, or 2.5 hours each. If you have four resources assigned to the task, it will give each resource 1.25 hours per day of duration. If you want WorkFront to calculate the planned duration of the task, based on how much labor it is going to take, use Effort Driven. I created a task with a Task Constraint of fixed dates. I then made the Duration Type Effort Driven. As I change the percentage allocation on the resource(s) assigned to that task, WorkFront recalculates the planned duration, but doesn’t change the dates. It says, for example, the planned duration is 0.1 days, with planned hours of 0.8 hours, but the dates remain fixed and unchanged. I’m not sure what that really tells me, except the duration and the dates become unrelated. --‘nuf of that Another consideration in figuring out why dates work out the way they do is that WorkFront, by default, has times associated with the dates. I have gone in and changed my views to show the hours. That is one reason why sometimes you have a task starting on 15OCT2016, with a duration of one hour, and the planned completion date is 16OCT2016. What you may not know is that the task start date (and time) is really 15OCT2016 at 1630 hours. Add one hour and given the calendar we are using, that pushes past 1700 hours, so it rolls a half hour of work into the next day, making the REAL completion date (and time) 16OCT2016 0830 hours. Does this help at all? Thanks, Eric

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Level 10
Hi Karen, We only use Simple Duration so that is all I know. In Simple, 1 day equals the number of hours you have in the Setup area for Typical Hours Per Work Day (Setup -> Project Preferences -> Projects ->Timeline Calculations). In our instance, it is 7 hours (we are nice and let our employees take a lunch break and that is built into the schedules). So if a task starts at 9am and has a 1 day duration, it will end at 5pm. Now if you want something from 9am on Monday to 5pm on Friday, you should put 5 Days in Workfront. Things to note: If you have a Monday holiday and have 5 Days on a task that starts on Wednesday at 9am, instead of ending at 5pm on Tuesday, it will push a day to accommodate the holiday (so it will end 5pm on the next Wednesday). If you really want that 5pm on Tuesday, change the duration to 1 week. That means literally 1 week and not 5 business days, which is usually one week. Also, if someone has Personal Time Off and are the only person on the task. It will accommodate that person's time off and push tasks. We had someone you wanted a lady on maturity leave. He put two days in his project schedule and it bumped the Planned Completion Date 8 weeks. Hope that was helpful.

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Level 10
Hi all, Nice explanation from Eric, as usual. Today I created a cheat sheet (see attached), because it seems that every couple of months I am researching the topic of Duration Types, then forget what I learned soon afterwards and need to research it again later. Hopefully this helps others also! Regards, David

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Level 10
Lovely. I’m going to send it out to my PMs. Thanks for pulling it together! Eric

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Level 6
Hi Eric Spending a little time on durations today. Can you clarify what happens when using ‘Simple’ - does this take into consideration a user’s time off? Laura Ray Project Support Analyst Bakkavor Information Systems Bakkavor Group West Marsh Road, Spalding, Lincolnshire, PE11 2BB, UK Direct: +44 (0)1775 763 010 www.Bakkavor.com // Laura.Ray@Bakkavor.com< [cid:image001.png@01D2254E.129BE890]

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Level 10
Hi: Yes, all duration types take into account the user’s time off and the Calendars. Can’t get away from that! Keep the questions coming. Thanks, Eric

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Level 6
Ok, thanks, I figured that must be the case but wanted to be sure. Laura Ray Project Support Analyst Bakkavor Information Systems Bakkavor Group West Marsh Road, Spalding, Lincolnshire, PE11 2BB, UK Direct: +44 (0)1775 763 010 www.Bakkavor.com // Laura.Ray@Bakkavor.com< [cid:image002.png@01D22555.42998190]

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Level 1
This is really great, thank you David.

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Level 4
As usual, Eric's responses are perfect. I did want to really emphasize his point that dates have a time element as well and how they can really trip things up when 1 day of duration appears on two days. This is usually the first thing I check when Planned Dates start looking wonky.