What is a Plus Delta Evaluation?

Plus Delta

Introduction to Plus/Delta

Maintaining a mindset of continuous improvement is vital for any Lean process. You cannot foster a successful Lean culture without the drive and intellectual curiosity to improve the systems through which the work is being completed.

We can only move forward and advance our thinking by first looking back at what we have already done, then considering what worked and what didn’t work. Plus/Delta is a retrospective technique that challenges teams to use recent work to shape future processes.

We must also carry a Respect for People into our work, as process improvement cannot occur unless we involve all key members involved in the work team to share their thoughts and perspectives freely. Continuous improvement must be driven by everyone, not just those leading the project.

plus delta chart example from lean construction institute

What is Plus-Delta?

A continuous improvement discussion performed at the end of a meeting, project or event used to evaluate the session or activity. Two questions are asked and discussed.

  • Plus: What produced value during the session?
  • Delta: What could we change to improve the process or outcome?
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Who Benefits From Utilizing Plus/Delta?

Plus-Delta Discussions Help Everyone

Design and construction teams of all sizes can benefit from making time for Plus/Delta discussions in their weekly work meetings. But Plus/Delta is an especially helpful tool for newly formed teams or inexperienced meeting facilitators as it drives productive conversation.

Experienced teams will find value in Plus/Delta discussions too, since you’ll never receive valuable feedback if you never ask for it. Valuable insights may go unspoken without regularly scheduled opportunities to share them, and processes that have fallen into a routine are at high risk of producing waste.

How to Incorporate Plus-Delta Into Processes

Plus/Delta discussions generally take place in the final 10 minutes of a meeting, but they can also be used as a tool for getting a meeting back on track if the conversation has veered away from the topic at hand. 

Either way, make room for the 10 minutes needed for a Plus/Delta discussion to occur when planning your meetings. Remain vigilant and don’t allow another topic to take over that time slot.

Plus-Delta Facilitators

It is the job of the meeting’s facilitator to ensure the Plus/Delta discussion happens as planned. It’s also their job to encourage members of the team to share their thoughts openly by fostering an environment that promotes a Respect for People.

During the meeting, the facilitator should take the time to explain what Plus/Delta is to the members of the team in case anyone needs a refresher or is participating in this exercise for the first time.

Plus-Delta Approaches

Plus/Delta discussions can either go around the room where everyone has a turn to provide feedback, or can be a more open and free-flowing conversation. More advanced teams use the latter approach.

Plus/Delta Discussions: Dos and Don'ts

Do

  • Focus on the processes themselves.
  • Encourage others in the group to share their thoughts, especially those who don’t usually participate in discussions.
  • Keep an open mind when receiving feedback.
  • Always keep the “action” in mind when discussing pluses and deltas. If someone provides a plus such as “we accomplished a lot of work yesterday,” determine what action occurred to create the conditions where work could be accomplished successfully.
  • Encourage people to provide both pluses and deltas. Both have value to the continuous improvement of processes.
  • Record all pluses and deltas provided.

Don't

  • Dismiss Plus/Delta discussions as just another box to check off on your to-do list.
  • Provide feedback on people or use this exercise as an excuse to air out dirty laundry.
  • Take deltas personally or push back against deltas provided.
  • Make a habit of ending the discussion early.
  • Be vague when providing feedback
  • Repeat pluses or deltas from previous meetings, if possible. Having the same delta means that the problem was not addressed the first time.

Example

A Plus/Delta chart is very simple to create. Just take a blank flipchart or white board and draw a line down the middle. Label one side at the top “Plus” and the other side “Delta.”

Below is a real Plus/Delta board from an MEP Phase Schedule meeting from the Turner Construction Company in 2005.

The Lean Construction Institute is committed to transforming the design and construction industry by providing Lean educational resources, conducting research, and facilitating local and national Lean events. It is only through the power of the LCI Corporate Members that LCI is able to offer the supplementary resources below.

Plus/Delta Resources

Downloads
plus delta quick sheet pdf cover photo
Plus/Delta Quick Sheet
Explore the what, when and how of Plus/Delta evaluation meetings when you download this quick sheet.
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plus delta cover photo pdf
Plus/Delta Chapter
Plus/Delta is a quick, simple retrospective to improve meetings, planning sessions or repetitive activities. Download to learn more.
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plus delta example cover photo pdf
Plus/Delta Example
Explore this real Plus/Delta board from an MEP Phase Schedule meeting from the Turner Construction Company in 2005.
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eLearning Courses
Introduction to Lean Project Delivery
Gain insight to Lean Project Delivery (LPD) by understanding how the Lean System connects People, Principles, and Practices to optimize results by shifting both mindset and behaviors. The key achievable goal of this course is to prepare and enable team members with a foundational understanding of Lean approaches for daily use within a project environment.
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Introduction to the Last Planner System®
This course will allow you to gain in-depth insight to the practical application of the Last Planner® System (LPS) through multimedia, hands-on interactions, diagrams, worksheets, and more. The key achievable goal of this course is to learn how to engage at all five levels of LPS effectively on a day-to-day basis with a team implementing the system.
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Effective Big Room
Gain a foundational understanding of the concept of a Big Room by learning the benefits, purpose, and implementation considerations. Understanding how to improve collaboration and drive transparency within your team. Identifying venue types, set up, and activities that work best for your projects. Learning how to effectively advance work and learning to support the success of future projects.
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Target Value Delivery
Gain an understanding of Target Value Delivery (TVD) by identifying the different phases and components that make up the delivery approach. Discover how the Lean components interact together to improve the process and outcome of the project.
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LCI Publications
Transforming Design and Construction: A Framework for Change

William R. (Bill) Seed, Executive Editor

A diverse set of practitioners collaborated to create the Transforming Design and Construction: A Framework for Change book based on the transformative projects and experiences of their Lean practices. The papers, presented in short chapter format, are intended to encourage discussion, learning and experimentation individually or with a team. Read the first and most popular book in LCI’s Transforming Design and Construction series to gain a high-level understanding of various Lean principles, strategies and methods.
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Target Value Delivery: Practitioner Guidebook to Implementation

Executive Editors: Kristin Hill, Katherine Copeland and Christian Pikel

Target Value Delivery: Practitioner Guidebook to Implementation was collaboratively written by a team of more than 20 Target Value Delivery (TVD) practitioners to provide current state practical guidance to implementing TVD with a project team. This guidebook portrays TVD as an umbrella over Target Value Production for construction and Target Value Design by taking a broader approach rather than focusing only on the design phase. Read LCI’s second book in the Transforming Design and Construction series to gain practical insight to current practices for implementing Target Value Delivery on any project.
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