Free Float vs Total Float in Project Management

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Aug 25, 2023

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Imagine project management as a complex puzzle, where tasks, milestones, and deadlines fit together to create success. Central to this puzzle are Free Float and Total Float - concepts that might seem alike but hold critical meanings for project planning, task links, and project victory. In this journey, we'll untangle the threads of Free Float and Total Float, uncovering their differences and how they shape real projects. Whether you're new to project management or experienced, this expedition will illuminate the role of Free Float and Total Float in steering projects toward triumph. Let's begin the journey of understanding these concepts in the world of project management.

What is Total Float?

Total Float is an essential concept that ensures projects stay on schedule. It essentially signifies how much of a delay a task within a project can endure without impacting the completion date; total float offers project managers flexibility when scheduling tasks without disrupting the final delivery of projects.

How to Calculate Total Float? 

Determining Total Float requires an in-depth analysis of task dependencies and project timelines, including early start (ES), and late start (LS) dates for tasks as well as their early finish and late finish dates (EF/LF). Here is how it works:

Total Float = LF - EF = LS - ES

Late Finish (LF) and Early Finish (EF) refer to the latest and earliest times a task can finish, respectively; Late Start (LS) and Early Start (ES) indicate when tasks can start without altering their project completion dates.

Examples of Total Float 

Let's examine a few examples to further demonstrate how Total Float works:

Example 1: Construction Project 

Imagine that you're conducting a multi-step construction project where pouring the foundation is one of several crucial steps. Your completion date is fixed; any delays must be avoided at any cost. Pouring can begin on day 1, finish early the following day 3, have a late start (LS) on Day 5, and a late finish (LF) by Day 7. Calculating Total Float:

Total Float = LF - EF = LS - ES

This equation calculates a total of 7 days with 3 equaling 5 and one being subtracted out for the purpose of pouring foundation tasks, although any delays exceeding this period will have an adverse impact on the project timeline.

Example 2: Software Development Project

Consider a software development project consisting of several tasks, including coding, testing, and deployment. Coding starts on Day 1, Early Finish is on Day 10 while Late Start (LS) occurs three days later with Late Finish being on Day 12. To calculate Total Float we simply divide this by four as calculated above:

Total Float = 12 - 10 = 3 -1

Total Float = 2 days

In this scenario, the coding task has a Total Float of two days; that means its completion can be delayed up to this threshold without impacting delivery schedules for projects. After that point, however, project schedules become compromised.

Significance of Total Float

Total Float provides project managers with an invaluable tool, enabling them to make informed decisions when it comes to task scheduling. If a positive Total Float indicates that tasks can be delayed without impacting project completion dates, allowing resource allocation more efficiently; while any delay would impact completion and require immediate attention and corrective actions.

Explain Free Float

Free Float is an essential concept in project management that holds the key to optimizing project schedules, smooth task interdependencies, and efficiently controlling risk. It represents the amount of time a task can be delayed without impacting subsequent tasks or the overall project completion date; in simpler terms, it demonstrates the flexibility available when delaying tasks that could otherwise delay project timelines.

Understanding Free Float is vital to project managers and teams as it allows them to make more informed decisions about task prioritization, resource allocation, and overall project sequencing. By identifying tasks with significant Free Float project managers can effectively allocate project resources while simultaneously managing tasks efficiently while mitigating risks of project delays.

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How to Calculate Free Float? 

Calculating Free Float involves taking an analytical approach that considers task dependencies and the critical path of the project. A critical path refers to the sequence of tasks that determine the quickest way for completion; any delays along this route could negatively affect project completion dates.

To calculate Free Float for any task, follow these steps:

  • First Step in Planning a Project: Define the Critical Path: First, identify the critical path for your project. This involves tasks that must be completed in a specific sequence in order to meet its timely completion, with zero Free Float; any delay on this path would delay its overall completion.
  • Establish Task Dependencies: First, identify the task for which you wish to calculate Free Float and identify its immediate predecessors and successors in terms of project schedule order.
  • Calculate Late Start Dates: Determine the Late Start dates for tasks by subtracting their duration from their immediate successor's Early Finish dates and deducting their duration from the Early Finish dates of their immediate successor's tasks. This gives a Late Start date which marks when they can begin without impacting other projects in their sequence.

Late Start = Early Completion of Task

  • Calculate Free Float: To determine the Free Float for any task, subtract its Early Start date from its Late Start date and subtract one day as its delay without impacting other tasks or project completion. This represents how long a task could be delayed without any negative repercussions or impact to completion.

Free Float = Late Start to Early Start

Free Float Examples 

Example 1: Event Planning

Imagine you're organizing a conference. You have tasks like booking the venue (Task A), arranging speakers (Task B), and creating promotional materials (Task C). Task B depends on Task A, and Task C depends on both Task A and Task B. The conference date is fixed, and all tasks need to be completed before that.

If Task A takes longer than expected due to delays in venue availability, it might eat into the time available for Task B and Task C. This would reduce the Free Float for both tasks, potentially impacting the quality of speaker selection and promotional materials.

However, even if the individual Free Float for Task B and Task C is exhausted, as long as their Total Float is not compromised, the conference can still happen on time. This means that you can allow some tasks to take a bit longer without endangering the overall event schedule.

Example 2: Product Development

Suppose you're managing a product development project, which involves design (Task A), prototyping (Task B), testing (Task C), and manufacturing (Task D). Each task is dependent on the completion of the previous task. Your project has a fixed launch date.

If there's a delay in Task A, it might eat into the Free Float of Task B. As a result, the time available for prototyping could be reduced, potentially affecting the quality of the prototype.

However, as long as the Total Float of Task B and the subsequent tasks (C and D) remain intact, the product can still be launched on time. Total Float accounts for the overall project deadline and ensures that even if one phase encounters delays, the project's end goal is still achievable.

Example 3: Film Production

Consider a film production project with tasks like scriptwriting (Task A), pre-production planning (Task B), filming (Task C), editing (Task D), and post-production (Task E). Task B depends on Task A, and each subsequent task depends on the completion of the previous one. The film's release date is fixed.

If there's a delay in Task A (scriptwriting), it might affect the Free Float for Task B (pre-production planning), causing less time for detailed planning, location scouting, and casting.

However, as long as the Total Float for Task B and the subsequent tasks (C, D, and E) remain positive, the film can still meet its release date. Total Float ensures that the entire project can endure some delays without missing the final goal of releasing the film.

In all these examples, Free Float and Total Float play crucial roles in project management. They offer insights into task flexibility, help manage risks, and ensure that projects can adapt to unexpected delays while still achieving their ultimate objectives.

Free Float vs Total Float 

Free Float and Total Float are two critical concepts that play a pivotal role in determining the success and efficiency of a project. While they might seem similar at first glance, they hold distinct meanings and implications that project managers must grasp to effectively navigate the complex landscape of project scheduling, resource allocation, and risk management.

1. Defining Free Float and Total Float:

Free Float: At its core, Free Float represents the amount of time a task can be delayed without affecting the subsequent task's start date. In other words, it signifies the flexibility available within the schedule of a specific task, without causing any delay to the overall project completion. Free Float identifies the window of opportunity during which a task can be rescheduled without causing a ripple effect on subsequent tasks or the project timeline.

Total Float: On the other hand, Total Float encompasses the total amount of time a task can be delayed without affecting the final project completion date. It considers the interplay between task dependencies, resource constraints, and project deadlines. Total Float accounts for both the flexibility within individual tasks and the project's overall timeline, offering insights into the level of buffer available before the project's deadline is compromised.

2. Distinguishing Factors:

  • Task Dependencies:

The fundamental difference between Free Float and Total Float lies in their focus on task dependencies. Free Float concerns itself with the immediate successor task, allowing adjustments without causing a delay to that task. Total Float, however, considers the broader context of all task dependencies and their impact on the final project deadline. This distinction is crucial as it guides project managers in making decisions that align with the project's holistic goals.

  • Impact on the Critical Path:

The concept of the critical path is pivotal in project management. It represents the sequence of tasks that, if delayed, would directly impact the project's completion date. Free Float does not affect the critical path, as it deals with the flexibility within non-critical tasks. Conversely, Total Float can influence the critical path, as it involves flexibility within tasks that are part of the critical path. Recognizing this distinction empowers project managers to prioritize their efforts where it matters most for project success.

  • Resource Allocation and Risk Management:

Resource allocation is a critical aspect of project management. Free Float allows project managers to allocate resources to non-critical tasks with greater flexibility, minimizing resource conflicts and optimizing resource utilization. Total Float, with its broader implications on project deadlines, aids in risk management by providing a buffer to accommodate unexpected delays or resource constraints.

  • Project Progress Tracking:

Effective project monitoring requires a nuanced understanding of task progress and its impact on the project timeline. Free Float offers insights into the rescheduling possibilities for specific tasks, allowing project managers to track deviations from the original schedule. Total Float, on the other hand, enables project managers to track the overall project timeline and identify potential delays early on.

 

AspectFree FloatTotal Float
DefinitionFree Float, also known as "slack," refers to the amount of time a task can be delayed without affecting the early start of its succeeding tasks.Total Float represents the duration by which a task can be delayed without delaying the project's final completion date.
CalculationCalculated by subtracting the task's early start date from the early start date of its next dependent task.Calculated by subtracting the task's early start date from the task's late finish date.
ImplicationProvides flexibility within the task's own path without affecting the project's completion date.Allows for flexibility within the task's path while ensuring the project's completion date remains intact.
Impact on ScheduleMay not impact the overall project schedule if the delayed task does not affect the critical path.Can impact the overall project schedule if the delayed task is on the critical path.
FocusFocuses on the task's relationship with its immediate successor.Focuses on the task's relationship with the project's completion date.
SignificanceHelps identify non-critical tasks that can be delayed without jeopardizing the project's completion.Identifies tasks critical to project completion and those that can be delayed without affecting the project's end date.
ExampleIn a construction project, delaying interior painting might not affect the final building completion date.In a software development project, postponing testing might extend the project's overall duration.
Calculation FormulaFree Float = Early Start of Next Task - Early Start of Current Task.Total Float = Late Finish of Current Task - Early Start of Current Task.
Utilization StrategyUseful for managing tasks that have dependencies but can tolerate some delay.Useful for managing critical tasks to ensure project completion on time.

 

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Conclusion

Mastering the difference between Free Float and Total Float empowers project managers to make informed decisions. Free Float provides leeway within task sequences, enabling flexibility without jeopardizing the project's completion date. On the other hand, Total Float safeguards project timelines by identifying critical tasks that must be closely monitored to avoid delays. The knowledge of these concepts is like a tool belt for project managers, allowing them to strategically navigate the challenges that arise during project execution.

Aspiring project managers seeking PMP certification training must grasp the significance of Free Float and Total Float. These concepts are essential not only for acing the certification exams but also for excelling in real-world project scenarios. A thorough understanding of these terms can set them apart as skilled project managers who can orchestrate projects with finesse, ensuring timely delivery and optimal resource utilization.

 

Frequently Asked Questions

Q: What is Free Float in project management?

A: Free Float represents the amount of time a task can be delayed without affecting the start date of its succeeding tasks.

Q: Why is Total Float important?

A: Total Float is crucial for identifying critical tasks that must be closely monitored to ensure project completion within the desired timeframe.

Q: Can Free Float affect the project schedule?

A: Free Float might not impact the project schedule if the delayed task is not on the critical path.

Q: How does Total Float impact project scheduling?

A: Delays in tasks with Total Float can affect the project's completion date, especially if critical tasks are delayed.

Q: Is Free Float more focused on tasks or the project completion date?

A: Free Float focuses on a task's relationship with its immediate successors.

Q: What does Total Float prioritize?

A: Total Float prioritizes a task's relationship with the project's final completion date.

Q: How can PMP certification training help understand these concepts?

A: PMP certification training provides comprehensive insights into project management concepts like Free Float and Total Float, ensuring a solid foundation for managing projects effectively.

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