1 pyright QSM Associates, Inc. All Rights Reserved Michael C. Mah Managing Partner QSM Associates, Inc. 75 South Church Street Pittsfield, MA 01201 413-499-0988 Fax 413-447-7322 e-mail: [email protected]Web Site: www.QSMA.com Boston SPIN October 19, 1999 Software Projects in Crisis Dealing with Dynamics of Imposed Deadlines
36
Embed
Copyright QSM Associates, Inc. All Rights Reserved 1 Michael C. Mah Managing Partner QSM Associates, Inc. 75 South Church Street Pittsfield, MA 01201 413-499-0988.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1Copyright QSM Associates, Inc. All Rights Reserved
Software Projects in CrisisDealing with Dynamics of Imposed Deadlines
2Copyright QSM Associates, Inc. All Rights Reserved
Industry Overrun Statistics
$250 Billion + Spent on IT Application Development
31% of Projects Will Be Cancelled, Representing $81 Billion in Losses
52.7% of Projects Will Overrun by >189%
Only 16.2% On-time,Under Budget
But with only 42% Original Functionality!
* Source: Standish Group, Dennis MA, 1995
3Copyright QSM Associates, Inc. All Rights Reserved
Other Noteworthy Trends
BILLION-DOLLAR OUTSOURCING DEALS DOUBLEIDC estimates that the number of large outsourcing contracts rose 100% between 1997 and 1998. (Source: *Computerworld*; www.idg.net/go.cgi?id=125306)
75% of organizations surveyed have backlogs running from seven months to over two years.
(Source: Chris Pickering's 1998 *Survey of Advanced Technology*;www.cutter.com/itgroup/reports/sat98.html)
4Copyright QSM Associates, Inc. All Rights Reserved
Worldwide Software Productivity Trend
The Good News: Over the last decade, productivity has increased fairly consistently. 10% faster speed, 25% less cost, about every 2.5 years.
The Bad News: It’s Not Enough. Demand continues to outstrip capacity.
Companies are reporting growing backlogs ranging from 7 months to over 2 years.
The Badder News: Continued labor shortages. The More Badder News: Don’t expect any
schedule relief in an “Internet Speed” economy.
5Copyright QSM Associates, Inc. All Rights Reserved
Reality Bites
“We don’t have the luxury of determining our schedules. They’re told to us. Then, given the time frame, we try to tell the client what we can build. In the end, we usually wind up working lots of overtime, because they want everything.”
- Manager of Development Wall St. Financial Firm
6Copyright QSM Associates, Inc. All Rights Reserved
Anyone Know What This Is?
7Copyright QSM Associates, Inc. All Rights Reserved
QSM Mixed Application Data Base
0.1
1
10
100
1000
100 1000 10000 100000 1000000 10000000
Effective Source Lines of Code
Calandar
Months
Real Time
Engineering
Info Systems
Impossible Zone
Are Deadlines/Plans in the “Impossible Zone”?
8Copyright QSM Associates, Inc. All Rights Reserved
Good to Know...
"As impressive as growth of the software industry has been, it is outpaced by growth of software-related litigation. It is not unusual for a large software development organization today to have upwards of 50 active cases on its hands."
Tom DeMarco, Cutter Consortium Bulletin, July 16, 1998
9Copyright QSM Associates, Inc. All Rights Reserved
Two “Old School” Waysof Estimation
Level of Effort, “Bottoms Up” Activity Based Method
Estimate and Add Up Person Months Force into Deadline
“Productivity Ratio” Based Method Divide Size into “Productivity” Calculate Effort Force Into Schedule
10Copyright QSM Associates, Inc. All Rights Reserved
Example # 1Level of Effort
“Here’s how we get an estimate. First, we look at each requirement. We estimate the person hours for the work based on complexity. We have an Excel spreadsheet with a table for the person hours needed to make a simple, modest, or complex change, on a simple, modest, or complex program. So, we get something like 20 person hours for high level design, 32 person hours for detailed design, another 40 for coding and unit testing for a given requirement.”
“That comes out to 112 person hours. We multiply that by 30% to get the integration. That makes 145.”
11Copyright QSM Associates, Inc. All Rights Reserved
Example # 1Level of Effort
“We add all the person hours up for the entire project. The grand total might add up to 34,000 person hours, or 200 person months. If we have a 10 month deadline, then it means we need to assign 20 people to the project.”
“If the schedule gets shortened on us to 6 months vs 10, then dividing 200 person months into a 6 month schedule means we need 33 people instead of 20.”
12Copyright QSM Associates, Inc. All Rights Reserved
Example # 2“Productivity Ratio”
“We ascertained that this project will be 800 total new + modified Function Points. Our productivity is 10 FP/staff month. So this project will take 80 staff months. We have 8 people on the team. So it will take 10 months.”
“If the schedule gets shortened on us to 6 months vs 10, then dividing 80 staff months into a 6 month schedule means we need 13 people instead of 8.”
13Copyright QSM Associates, Inc. All Rights Reserved
Violation of Brook’s Law
Manpower and Time are not interchangeable. That is, you can not cut schedule in half by doubling the number of staff.
- Fred Brooks, The Mythical Manmonth
(Corollary: You can not get a baby in 1 month with 9 women.)
14Copyright QSM Associates, Inc. All Rights Reserved
Laws of Cause and Effect
The fundamental, or core metrics of time, cost, and quality, across small, medium, and large projects (size) are interdependent.
We, as managers and developers, have treated them as independent variables.
For example, we want to believe that we can keep a deadline fixed in spite of size growth. The think the effort is the effort, and reliability should not be impacted much (we hope).
Not only are they interdependent, but data has revealed to us that changes in one dimension can result in geometric impacts in another dimension
15Copyright QSM Associates, Inc. All Rights Reserved
How DevelopmentLifecycles Behave
A Pop Quiz:
“If you tried to shorten the schedule on an application development project by adding staffto say, double (20 people versus 10), how muchwill you able to compress it? Will defects go upor down, and by how much?”
16Copyright QSM Associates, Inc. All Rights Reserved
How SoftwareLifecycles Behave
Answer:
Schedules will only compress (nominally) byabout 20 percent.
Defects typically rise by about 6 fold.*
Rule of Thumb: “20/200/6x”
*Source: QSM Industry Database Statistics
17Copyright QSM Associates, Inc. All Rights Reserved
When Time & Effort are “Fixed” Something’s Got to Give...
SizeTime
Effort
Defects
18Copyright QSM Associates, Inc. All Rights Reserved
“Feature Creep” - Impact on Quality with Fixed Schedule
Time Profile
11
12
13
14
15
16
17
18
Mo
nth
s
1 2 3 4 5Solutions
FOC MTTD Profile
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Day
s
1 2 3 4 5Solutions
Size Profile
60
70
80
90
100
110
ES
LOC
(thou
san
ds)
1 2 3 4 5Solutions
Solution 4
TimeEffortUinf CstPk StaffMTTDSize
14.06116.40
106712.922.15
87000
MonthsPM$ 1000PeopleDaysESLOC
100% Prob
38% Prob100% Prob 1% Prob
PI 17.0
Schedule Fixed at 14 Months
Size Increases in 5KSLOCIncrements from 72K to 92K
Quality Levels Cut in Half - MTTD 3.5 Days to 1.75 Days
19Copyright QSM Associates, Inc. All Rights Reserved
Size
Probabilityon
Time
Scenario: Size Growth,or “Feature Creep”
20Copyright QSM Associates, Inc. All Rights Reserved
Compress Schedule: Plan 1
uses 9 People
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13
Staffing 9 People 69 Staff Months MTTD = 3.2
Days
Elapsed Time - Months
21Copyright QSM Associates, Inc. All Rights Reserved
Compress Schedule: Plan 2 uses 24 People
0
10
20
30
40
50
60
70
1 2 3 4 5 6 7 8 9 10 11 12 13
Staffing
Elapsed Time - Months
24 People 144 Staff Months MTTD = 1.2 Days
22Copyright QSM Associates, Inc. All Rights Reserved
Dangerous Productivity Metrics: Only 2 Dimensions
Lines of Code
Staff Month
Function Points
Staff Month
23Copyright QSM Associates, Inc. All Rights Reserved
Summary: Both Ratios Are Equally Poor Measures
Size = 75,000 New and Modified SLOC 707 FP
PeakStaff
Sched(Mos) FP/PM
69
14243366
13.612.311.310.29.58.3
15.410.27.34.93.82.1
LOC/PM
16301086 773 520 398 225
LOC/DAY
254281306339364417
Effort(PM)
46 69 97144188333
24Copyright QSM Associates, Inc. All Rights Reserved
SEI Special ReportCMU/SEI-95-SR-005
1) A Corporate Memory (Historical Database)
2) Structured Processes for Estimating Size and Reuse
3) Mechanisms for Extrapolating from Demonstrated Accomplishments on Past Projects
25Copyright QSM Associates, Inc. All Rights Reserved
4) Audit Trails (Values for Cost Model Parameters Used to Produce Each Estimate Are Recorded and Explained)
5) Integrity in Dealing with Dictated Costs and Schedules
6) Data Collection and Feedback Processes That Foster Capturing and Correctly Interpreting Data from Work Performed
SEI Special ReportCMU/SEI-95-SR-005
26Copyright QSM Associates, Inc. All Rights Reserved
The Role of Measurement, and Commitments
Estimation& Planning
Control&
Forecasting
Support FutureCommitments
ManageCommitmentCommitment
Analyze Performance on Commitment
HistoryRepository
Assess Viable Strategies
Monitor Status & ReplanPost Project Analysis
Make Commitment
27Copyright QSM Associates, Inc. All Rights Reserved
Mapping to An “Efficiency”, or “Productivity Index”
Productivity Index
Functionality(Size)
Effort Time
~ Goodness(Quality/Defects)
28Copyright QSM Associates, Inc. All Rights Reserved
Example PI CalculationSize = 375 Function
Points 35,000 LOC
Effort = 24 Person-Months
Time = 6 Months
*PI = SIZE
TIME EFFORT= 17
Project Staffing Profile
23
5 5 5
4
0
1
23
4
5
6
Jan-97 Feb-97 Mar-97 Apr-97 May-97 Jun-97
29Copyright QSM Associates, Inc. All Rights Reserved
Productivity IndexIndustry Baselines - 1997
Category PI STD Dev
Business 17.3 +/- 4.1
System Software 13.7 +/- 4.9
Telecom 12.2 +/- 4.0
Scientific 12.1 +/- 3.5
Process Control 12.1 +/- 3.4
Command & Ctrl 11.3 +/- 4.3
Avionic 8.2 +/- 4.8 Real-time 7.8 +/-
3.8 Microcode 6.3 +/-
2.8
FinanceRetailInsuranceOthers
30Copyright QSM Associates, Inc. All Rights Reserved
Given a Certain Development Efficiency (PI),
And Given the Deadline With a Team of “X” People ...
“Real World Estimation”
How Much Functionality Can We Build?
How Much Functionality Should We Promise?
31Copyright QSM Associates, Inc. All Rights Reserved
Fitting Trendlines to DataQ SM M ixed Application Data Base
Effective Source Lines of Code
Calandar
Months
0.1
1
10
100
1000
100 1000 10000 100000 1000000 10000000
A v era g e
1 S ig m a L ess T im eT o p 1 6 % o f th e d a ta b a se
1 S ig m a M o r e T im eB o tto m 1 6 % o f th e d a ta b a se
32Copyright QSM Associates, Inc. All Rights Reserved
Positioning Projects Vs.Industry Trends - Example
Q SM M ixed Application Data Base
Effective Source Lines of Code
Calandar
Months
0.1
1
10
100
1000
100 1000 10000 100000 1000000 10000000
C ompany XYZProject D ata
P ro je c ts P o s itio n R e la tiv e to In d u s try T re n d sU s in g th e A p p ro p ria te S iz e a n d A p p lic a tio n T y p e
M ain Build - ScheduleSystem Software D ata
33Copyright QSM Associates, Inc. All Rights Reserved
In Summary...
Productivity is Multi-Dimensional. 2-Dimensional Measures Are Inadequate
Visual Explanations Are Vital
The Need to Quantify Size of New, Modified, and Total Delivered Functionality Will Arise
No One Size Measure is a “Silver Bullet”
34Copyright QSM Associates, Inc. All Rights Reserved
In Summary...
Metrics of Schedule, Cost, and Quality are Interdependent.
Productivity Metrics in the Form of Ratios Are Dangerous. They Omit Time. Time = Deadline. Deadline is the Independent Variable, Upon Which the Dependent Variables Behave.
35Copyright QSM Associates, Inc. All Rights Reserved
Establishing a Software Management Program:Lessons Learned
Management Awareness and Acuity are Essential
A Metrics “Champion” is Essential
Collect Core Metrics; “Know Your Capability”
Dull Metrics Means You’ve Got the Wrong Metrics
Turn Numbers Into Pictures, Show the Right
Dimensions, Reveal What is Hidden
36Copyright QSM Associates, Inc. All Rights Reserved