1. Project Metrics
Infsy 570
Dr. R. Ocker

2. goal of metrics
to improve product quality and development-team productivity
concerned with productivity and quality measures
measures of SW development output as function of effort and time
measures of usability

3. terms: measure measurement metric
quantitative expression of an attribute of a product or process
measurement
the act of determining a measure
metric
quantitative measure of the degree to which a system, component or process possesses an attribute

4. terms: indicator process indicators
a metric that provides insight into the SW process or project
enables manager to adjust (improve) the process or project
process indicators
allow assessment of process in terms of what works and what doesn’t

5. Terms: project indicators allow manager to
(1) assess status of ongoing project
(2) track project risks
(3) uncover problem areas
(4) adjust tasks or workflow
(5) evaluate team’s ability to control quality

6. metrics apply to process - used to develop the SW
project - specific SW development project
product - SW produced
many of the same metrics apply to both the process and project domains

7. 1. Process metrics and SW process improvement
How to improve SW quality and organizational performance?
fig 4.1 text, fig.2 Paulish & Carleton:
Factors that influence quality:
people - skills and experience of SW people
technology - used in development (e.g. CASE)
product complexity
process - glue that ties it all together

8. motivation to improve process:
results from business need, e.g. strong competition, need increased profitability
“The only rational way to improve any process is to measure specific attributes of the process, develop a set of meaningful metrics based on these attributes, and then use the metrics to provide indicators that will lead to a strategy for improvement.”
... process metrics are strategic

9. Process improvement approach (fig. 3, Paulish et al.)
business need
motivation to improve
assessment (of current practices and process maturity level)
improvement methods selected
metrics measure impact

10. Process improvement approach (fig. 3, Paulish et al.)
business establishes goals to improve process over period of time
defines measures to gauge progress
when data indicate process problems - take corrective action

11. Software process improvement method
integrated collection of procedures, tools, and training for increasing product quality, improving development-team productivity, or reducing development time

12. Some outcomes of an improved SW process might include:
fewer defects
earlier identification and correction of defects
faster time to market
better predictability of project schedules and resources

13. Types of process metrics:
private vs. public metrics
SW process improvement should begin at the individual level

14. some private metrics: defect rates by individual
defect rates by module
errors found during development

15. public metrics use information from individual and team metrics
some public metrics:
project-level defect rates
effort
calendar times

16. 2. Project Metrics project metrics are tactical
used by project manager to adapt project work flow and technical activities
i.e. guide adjustments to work schedule to avoid delays; assess product quality on an ongoing basis

17. attention to metrics should lead to reduction in project costs:
as quality improves
errors are minimized
rework reduced

18. estimation first application of project metrics on SW project
metrics collected from past projects used as basis for time and effort estimates
as project advances, collect production rates and error metrics

19. 3. Software Measurement
direct measures vs. indirect measures

20. direct measures direct measure of process: direct measure of product:
cost and effort
direct measure of product:
lines of code (LOC)
execution speed
defects per time period

21. Indirect measures indirect measures of product: functionality quality
complexity
reliability
maintainability

22. Consolidation of metrics
individual metrics combined to develop project metrics
project metrics consolidated to create process metrics
how to combine metrics from different projects?
normalization - enables comparison

23. 3.1 Size-oriented metrics
derived by normalizing quality and/or productivity measures
use size of the SW to normalize
size-oriented measures include:
LOC
effort $
errors
defects
people

24. normalizing suppose choose LOC as normalization value
then can compare across projects:
errors per KLOC
defects per KLOC
$ per LOC

25. estimates
very important to estimate the associated cost of development early in the development project
to have accurate cost predictions, need accurate estimates of project size

26. Software size
primary factor affecting SW cost is the SIZE of the project
estimating SW size is DIFFICULT
most frequently used metrics for measuring size:
lines of code (LOC)
function points
some controversy regarding using LOC as key normalization measure

27. LOC pros:
easily counted (after the fact, once you choose a counting method)
used a lot

28. LOC cons:
lack of universally accepted definition for what a line of code really is (there are at least 11 different variations for counting LOC)
programming language dependent
difficult to use to estimate project size and effort - don’t have enough information at beginning of project to accurately estimate LOC

29. 3.2 Function-oriented Metrics
use a measure of functionality as the normalization value
formula estimate
functionality cannot be measured directly, but must be derived using other (direct) measures
method of quantifying size and complexity of system in terms of functions that system delivers to user

30. fig. 4.5 computing function points
measurement parameter count simple average complex
1. number of user inputs ??? = X
2. number of user outputs ??? = X
3. number of inquiries ??? = X
4. number of files ??? = X
5. number of external interfaces
??? = X
count=total XX

31. You must perform the count:

32. 1. number of user inputs
each unique user input that provides application-oriented data to the SW
includes input that enter directly as transactions from the user, and those that enter as transactions from other applications (e.g. input file of transactions)

33. 2. number of user outputs
each user output that provides application-oriented information to user (reports, screens, error messages, etc.)
include reports and messages to the user and reports and messages to other applications (e.g. files of reports and messages)

34. 3. number of inquiries
inquiry is an on-line input that results in generation of an immediate SW response in form of an on-line output
each distinct inquiry is counted

35. 4. number of internal files
include each logical file or if using a DB, logical grouping of data, that is generated, used and maintained by the application

36. 5. number of external interfaces
files passed or shared between applications should be counted
i.e., machine-readable interfaces (e.g., data files on tape or disk) that are used to transmit information to another system are counted

37. to compute: 1. classify and count the five user function types
2. adjust for processing complexity
determine complexity value associated with each count
can develop criteria for determining whether simple, average or complex
3. make the function points calculation
FP= count-total X [ X  Fi
Fi (i=1 to 14) are complexity adjustment values
see table 4.1

38. answer questions such as:
Is performance critical?
Are the master files updated on-line?
Is the code designed to be reusable?
Use function points to normalize measures of SW productivity and quality.

39. FP Pros: programming language independent
based on data more likely to be known early in the project (still need requirements specs. or design specs.; see Matson et al.)

40. FP Cons: computation based on subjective data
designed to measure business-type applications (not good for technical or scientific applications)

41. 4. Metrics for SW Quality
focus on the process, the project and the product (as do productivity metrics)

42. Factors that affect quality
product operation - using it
product revision - changing it
product transition - portability

43. Measuring quality correctness
degree to which SW performs its required function
defects per KLOC - most common measure for correctness
maintainability
ease with which a program can be corrected, adapted, or enhanced

44. Measuring quality MTTC - mean time to change - integrity
simple metric - time it takes to analyze, implement change, test it, and distribute it to users
integrity
measures system’s ability to withstand attacks on its security

45. Measuring quality usability measured using 4 characteristics
quantify user friendliness
measured using 4 characteristics
1. physical/intellectual skill required to learn the system
2. time required to become moderately efficient
3. net increase in productivity when system used
4. users attitudes toward the system

46. 5. Integrating metrics within the SW process
majority of SW developers do not measure
problem is cultural
measurement results in cultural change
resistance, often due to fear

47. barriers to implementing process improvement methods (Paulish et al.)
1. getting started
orgs. need to conduct an assessment (e.g. Capability Maturity Model)
2. staff turnover
downsizing is difficult environment for process improvement
need champions to stick around
3. dedicated resources
need full-time dedicated resource(s) to implement process improvement methods

48. barriers to implementing process improvement methods (Paulish et al.)
4. management support
it’s necessary
5. time restrictions
you’ve got to make the time to institute it

49. Some preliminary recommendations (Paulish et al.)
1. use capability maturity model as guide to improvement
it provides a framework showing which methods to use based on current maturity
2. conduct an assessment at beginning
to identify priorities for improvement and build consensus within org.

50. Some preliminary recommendations (Paulish et al.)
3. pick a few process improvement methods
implement these effectively
4. pay attention to implementation of methods
includes good training and management
5. some process improvement methods easier to implement than others

51. remember...cultural factors are substantial
have significant impact on success with adopting software process improvement methods
“the collection of quality metrics enables an organization to ‘tune’ its software engineering process to remove the ‘vital few’ causes of defects that have the greatest impact on software development”