What's with all these Appendix pages in our decks?

I was just asked by a friend why the former McKinsey Partner to whom she reports wants PowerPoint decks with detailed Appendix pages, so that's the topic addressed in this post. I'll go over...

1. Definition of Appendix or back-up pages
2. Why McKinsey consultants use Appendix pages

• In team and client discussion documents
• In client deliverable documents

What are Appendix or back-up pages?

Consultants spend a lot of time working in Microsoft PowerPoint (PPT) creating pages that are assembled into decks.  Most McKinsey decks are comprised of two primary sections, the main deck and the Appendix, also referred to as back-up pages.  It's not uncommon for the Appendix to be significantly longer than the main deck.  If the main deck tells the story, the Appendix contains all of the supporting evidence.

Why do we use Appendix or back-up pages?

Appendix pages take as much time and effort to make - sometimes even more - as the pages in the main deck.  The reason for including Appendix pages often depends on the reason for the document.  Generally speaking, McKinsey engagement teams create two types of decks: 

DISCUSSION DOCUMENTS

These are decks used to drive client or team discussions - examples include progress updates and collaborative problem solving sessions.  In these cases the main deck is often light, featuring just enough thought starters and information to keep the conversation moving in the right direction.  In these decks, Appendices are often used to include data or evidence that could contribute to the discussion.  They might not be included in the main deck if they might be too leading or controversial, but teams might want to have data in their back pocket in case facts or hypotheses are called into question.

CLIENT DELIVERABLES

There are usually more substantial decks - sometimes hundreds of pages long - that are given to the client at major milestones (e.g., Steering Committee meetings) and/or at the conclusion of an engagement.  These extensive, detailed documents contain all of the data, findings, and insights generated over the course of the study.  I've heard several reasons why these decks contain so many Appendix pages:

• Keep the storyline of the main deck crisp and clear by moving the supporting documentation and details to the Appendix where they will be out of the way but available for reference.  Trackers (I'll address these in a future post) can be used to link sections of the main deck to their corresponding Appendix pages

• You never know when a certain piece of information will be helpful so we might as well hand it off to the client.  Sometimes the data comes in handy during the meeting.  In most cases the material in these documents is pre-wired or syndicated with key clients prior to the meeting to ensure everyone is aligned with the content.  But, questions still come up, in which case supporting evidence and analyses in the Appendix can be referenced to help answer difficult questions or resolve disagreements

• Giving the client their money's worth is the most cynical reason I've heard for why we pack the Appendix full of lots of data, exhibits, and analyses.  The rationale is that clients pay high fees for the engagement so they're expecting a large volume of work product along with the insights and recommendations contained within the main deck.  I don't necessarily agree with this thinking, but I have heard it mentioned