11-1 11-2

Master Scheduling
CHAPTER  The heart of production planning and control
11  It determines the quantity needed to meet demand 
from all sources.
 It interfaces with

Master Scheduling  Marketing

 Capacity planning
Covers pages 477-482 only.  Production planning

 Distribution planning

 Provides senior management with the ability to 
Homework problems # 19,20,21,22 on page 491. determine whether the business plan and its strategic 
objectives will be achieved.

11-3 11-4

The Master Scheduler ( a job title) Master Scheduling Process (Fig. 6)

 The master scheduler’s duties:
 Evaluating the impact of new orders

 Providing delivery dates for orders

 Deals with problems

 Evaluating the impact of production or delivery 
delays
 Revising master schedule when necessary because 
of insufficient supplies or capacity
 Bring instances of insufficient capacity to the 
attention of relevant personnel so they can 
participate in resolving conflicts

11-5 11-6

Updating Projected On-

On-hand Inventory Projected On-
On-hand Inventory

Projected on‐hand Inventory from Current week’s

inventoryy
= previous week
- requirements

Current week’s requirements = Max (forecast, order)
11-7 11-8

Projected On-
On-hand Inventory Available to Promise (ATP) Concept
Lot size = 70
LT = 2 weeks
The available to promise (ATP) is the period’s MPS 
quantity minus the sum of customer orders 
occurring before the next MPS receipt. During the 
first master schedule period, the ATP quantity 
includes the on‐hand balance (inventory).
The ATP quantity is only calculated for the first 
(completion) week and for subsequent weeks in which there is 
MPS start 70 an MPS quantity.

11-9 11-10

Available to Promise (ATP) Calculation Available to Promise (ATP)

a. Concept
Amount of MPS that can still use to meet new 
booking requests, considering current on‐hand, 
MPSt , and COt
b. First Week:
ATP=current OH + MPS in first week ‐ cumulative 
COt occurring before the next MPS receipt.
c. Subsequent Weeks:
Only for weeks when an MPS quantity arrives.
ATP= MPS of the week ‐ cumulative COt occurring 
before the next MPS receipt.

ATP Example
11-11 11-12

ATP Order
Order--Acceptance Example
Order Policy: 80 units
Item: 3-in. gate valve

April May Based on the previous slide, should the following 

Quantity
on Hand:
45
1 2 3 4 5 6 7 8 orders be accepted? 
Forecast 20 20 20 20 40 40 40 40

Customer
orders 23 15 8 4 0 0 0 0 Order Amount (units) Week Requested
(booked)
Projected
on-hand 22 2 62 42 2 42 2 42
1 5 2
inventory
2 38 5
MPS quantity 0 0 80 0 0 80 0 80
3 24 3
ATP inventory 7 68 80 80
4 15 4
11-13
Order Policy: 80 units
Item: 3-in. gate valve

Updated ATP
April May
Quantity 45
on Hand: 1 2 3 4 5 6 7 8

Forecast 20 20 20 20 40 40 40 40

Customer
orders 23 20 32 4 38 0 0 0
(booked)
Projected
on-hand 22 2 50 30 -10 30 -10 30
inventory

MPS quantity 0 0 80 0 0 80 0 80

ATP inventory 2 6 80 80