Essential Elements of Backlog Measurement and Analysis

Backlog. What is it? What does it mean? Why bother? These are questions that, surprisingly, have many answers none of which are ever the same or fully complete.

One would think that, for a concept that is said to be one of the most important in the field of labor management, backlog would have more definition and interpretation. It is not to say that the backlog issue is not important, just that it is one of those concepts that can be approached from more angles than a game of pool.

Backlog is, in fact, a very important tool. Backlog can be used to produce and analyze budget and staffing requirements, balance workloads across a labor force, and much more.

Simply put, backlog classifies work that, for whatever reason, has not been completed.

The basics
Every work order in any organization's backlog has five primary characteristics that can be used to further define the meaning and forward the analysis of the backlog. These characteristics are status, classification, priority, age, and estimated duration.

Backlog work status (Fig. 1). The most basic example of this characteristic is that the work order is completed, cancelled, or open. To fit the bill for backlog, it is the open work orders that concern us.

What many fail to take into account is an important division of the backlog that involves the concept of attainment. Attainment is the existing status of a work order which suggests that it either can have labor applied and/or be completed, or that it is temporarily in a holding status for specific reasons.

The elements of unattainable backlog include work orders that have recently been approved and remain unguided, those waiting for materials, and those waiting for planning. The status of waiting approval is intentionally left out of these categories since these work orders have not yet been determined to be feasible future work.

Likewise, attainable backlog applies to work orders that are readily available for processing and completion. These include waiting for scheduling, scheduled, and in progress.

This division is essential to good backlog management for a simple reason. The attainable work is the backlog available for processing and the workload that should be focused on for future labor assignments. The unattainable backlog is essentially the work on hold and is not readily available to the organization.

Backlog work classification (Fig. 2). Work orders can, and often are, divided into logical groups to account for the nature of the work. These work types can fall into two categories.

Direct labor directly contributes to productive maintenance goals. Indirect or overhead labor does not directly contribute to productive ends. These hours include the functions of administrative tasking and training. Fig. 2 shows some common work types associated with these categories.

Backlog work priorities (Fig 3). Some people may say, We just don't use priorities. But priorities are used whether or not they are actively recorded in a computerized maintenance management system (CMMS).

A primary example is that more urgency is placed on jobs that affect safety and production. Also, no one can say that if a company executive requests work to be done, no matter what it is, that more urgency will apply to that work just to keep a good reputation with upper management.

Priorities are essential to backlog management because they show how important the hours in the backlog are to an organization.

Some might reflect that their operation processes multiple thousands of work orders per week and that the task of prioritizing them would be time prohibitive and not worth the effort. Fig. 2 shows how this issue is solved with relative ease by simply establishing default priorities in conjunction with work classification. These defaults should be set as a guide for work orders when they are created and should not be rigid values, since priorities on any one work order can change based on circumstances.

Fig. 3 shows a basic representation of a priority system. It is not as important how priorities are set up as how they are controlled. In Fig. 3, the shelf life column demonstrates the true meaning of the system. This shelf life determines how long a work order of any priority would be allowed to remain in backlog before raising questions and/or concerns about its processing.

Backlog age (Fig. 4). Determining the age of backlog work orders is an important element to use when thinking about the validity of work yet to be done. For simplicity sake we'll look at a military concept, the 30/30/60/90.

As demonstrated in Fig. 4, this concept is simply grouping work orders into zones depending on their age. These zones are used as control points for decisions on cancellations and changes in priorities.

Probably the simplest contributing element of good backlog management is using planning to produce an estimate for labor requirements on the work orders. Because backlog is measured in hours, the more planned work orders in the backlog, the more accurate that measurement will be.

For example, a maintenance shop has 3590 hours in backlog, and these hours apply to 704 individual work orders. This shop has 16 percent, or about 108, of these work orders left unplanned. If these work orders were actually 16 percent of the labor in the backlog, they would be worth around 682 hours. This is a very defined concept of what backlog really is. But, what does it all mean?

Backlog representation (Fig. 5). Representing backlog statistics is essential when making decisions based on its content because those decisions must be justified to someone who, more than likely, has little knowledge of how to read the supporting data. In this case, having a uniform format for displaying the data makes for faster reading and better understanding of its meaning.

Fig. 5 is an example of backlog representation that uses many of the backlog characteristics previously mentioned. The layout takes advantage of the attainment division of backlog status, while providing a section reflecting the total backlog. Next, the report separates the data by age and priority, and finally summarizes the count of existing work orders, estimated durations, and the backlog coverage index, which is a simple percentage showing how many of the work orders have had duration estimates planned.

As stated before, because backlog is measured in planned hours, providing estimated durations for backlog work orders determines the accuracy of the end data and the decisions that can ultimately be made. Future articles in this series will cover backlog measurement and its analysis. MT


This e-mail address is being protected from spambots. You need JavaScript enabled to view it is a business analyst with Amgen, Inc., MS 21-2-A, One Amgen Center Dr., Thousand Oaks, CA 91320-1799

BACKLOG CHARACTERISTICS: WORK STATUS

Waiting Scheduling (WSCH)
Scheduled (SCHED)
In Progress (INPRG)

Attainable Backlog

Approved (APPR)
Waiting Materials (WMATL)
Waiting Planning (WPLAN)

Unattainable Backlog

Completed (COMP)
Cancelled (CANX)
Closed (CLOSE)

Terminal Work Orders

Waiting Approval (WAPPR)
Waiting Review (WREV)

Transitional Work Orders

Fig. 1. Attainable work is the backlog available for processing and the workload that should be focused on for future labor assignments.

back to article

BACKLOG CHARACTERISTICS: WORK CLASSIFICATION

Work Type Classification

Default Priority

Direct Labor

Emergency Maintenance (EM)

0

Preventive Maintenance (PM)

1

Corrective Maintenance (CM)

1

Routine Maintenance (RM)

2

Capital Projects (CP)

2

Overhead Labor

Administrative Tasking (AT)

3

Meetings (MT)

3

Training (TR)

3

Inspection Summaries (IS)

3

Fig. 2. Various types of work fall into two categories.

back to article

BACKLOG CHARACTERISTICS: WORK PRIORITIES

Priority

Normal Shelf Life

0 Emergency

Less than 7 days

1 Immediate

7-30 days

2 Priority

15-60 days

3 Routine

30-90 days

4 Hold

Special

Fig. 3. Priorities are essential to backlog management because they show how important the hours in the backlog are to an organization.

back to article

BACKLOG CHARACTERISTICS: BACKLOG AGE

Class

Age (in days)

Zone A

Less than 30 days

Zone B

30-60 days

Zone C

60-90 days

Zone D

Greater than 90 days

Fig. 4. The concept of age is simply grouping work orders into zones depending on their age in order to make decisions on cancellations and changes in priorities.

back to article

BACKLOG CHARACTERISTICS REPRESENTATION

XYZ Corporation
Facilities Division (Production)
Current Backlog Analysis Report
Report Date:
10/29/03
12:42:54 p.m.

Attainable Backlog

Under 30 Days Old

Over 30 Days Old

Over 60 Days Old

Over 90 Days Old

Totals

WO Priority

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

0

6

11.40

100.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

6

11.40

100.00%

1

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

2

181

172.20

49.72%

60

161.20

91.67%

26

93.60

76.92%

418

2960.85

99.52%

685

3387.85

84.82%

3

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

4

4

76.00

25.00%

1

0.00

0.00%

1

0.00

0.00%

4

106.50

75.00%

10

182.50

40.00%

Totals

191

259.60

50.79%

61

161.20

90.16%

27

93.60

74.07%

422

3067.35

99.29%

701

3581.75

84.31%

Unattainable Backlog

Under 30 Days Old

Over 30 Days Old

Over 60 Days Old

Over 90 Days Old

Totals

WO Priority

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

0

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

1

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

2

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

2

4.90

100.00%

2

4.90

100.00%

3

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

4

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

1

4.00

100.00%

1

4.00

100.00%

Totals

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

3

8.90

100.00%

3

8.90

100.00%

Total Backlog

Under 30 Days Old

Over 30 Days Old

Over 60 Days Old

Over 90 Days Old

Totals

WO Priority

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

No. WO

Hours

BLCI

0

6

11.40

100.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

6

11.40

100.00%

1

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

2

181

172.20

49.72%

60

161.20

91.67%

26

93.60

76.92%

420

2965.75

99.52%

687

3392.75

84.86%

3

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

0

0.00

0.00%

4

4

76.00

25.00%

1

0.00

0.00%

1

0.00

0.00%

5

110.50

80.00%

11

186.50

45.45%

Totals

191

259.60

50.79%

61

161.20

90.16%

27

93.60

74.07%

425

3076.25

99.29%

704

3590.65

84.59%

back to article