Task ID and Effort Flashcards
A task that we call an action
non-decomposable
A task that we call an activity or process
decomposable
Work package
The ideal level of detail, or amount of work that is small and specific enough that it can be estimated reliably
Work breakdown structure (WBS)
A way to identify tasks at a useful level of abstraction.
It is deliverable-oriented hierarchial decomposition of work done by the project team
What does Work Breakdown structure (WBS) hope to achieve
to achieve project goals or produce project delieverables
3 formats of WBS
tree
hierarchy diagram
hierarchial list
Parts of WBS tree
nodes- are items of work in project
root- is project name
leaves- are more detailed specifications of work
Decomposition strategies of BS (4)
Project phases
Organizational units
Physical decomposition
Geographical location
Decomposition Levels
1) deliverables
2 and 3 - features and functions
WBS strategy - One hundred percent rule
The nodes descended from a parent represent 100% of the work of the parent, but no work outside the project
WBS strategy = Mutually exclusive siblings
No sibling in WBS have overlapping work. (else leads to inflated effort estimate and confusion about work assignments)
WBS strategy = 8/80 rule
Work packages (leaf nodes) require between 8 to 80 person-hours of effort. Helps to determine wether a node should be decomposed (work can be done by one person in one day to two weeks is considered small enough to estimate reliably
Best process for creating a WBS
- gather project team and stakeholders in a meeting in which WBS is created on whiteboard
- participants make a list of items at level one on own
- group comes to consensus on level 1
- Delieveralbes (product features and fuctions) listed in WBS
- stakeholders leave
- lower levels consisting of development tasks and activieties are then filled in by developers
Effort Estimation - Analogy
Current project similar to past project, effort to complete should be roughly same as effort required to complete past project
Effort Estimation - WBS to Effort
Given complete work breakdown structure for project, can estimate effort required for each work package and then sum estimates to generate effort estimate for entire project. (but WBS must be accurate)
Effort Estimation - Size to Effort
Given estimate of size of software product, and relationship b/w product size and effort can generate estimate of project effort
Functional measures of size
Dominated in units that are a direct relection of functionality being provided by the program
- num of pages in WWW application
- num of reports in database application
- num of windows in GUI
Non functional measures of size
Direct reflection of program structure
- lines of code (hard to count beforehand)
- nm of classes
Advantages of functional measures vs nonfunctionla
1) largely independent of technology and platform being used
2) user-focused and easier to explain to nontechnical stakeholders
Function point analysis
Functional mesure that has 5 different kinds of functionality (base functiona lcomponenet types)
3 are related to processes/transactions
2 related to data storage
External Inputs (EI)
Processes that provide data that will be used or stored by the product.
Ex. adds new employees to a file or table of employee records
External Queries (EQ)
Process that retrieve stored data (without adding value or information but, perhaps, providing formatting)
Ex, retrieves all employees in a file or table
External Outputs (EO)
Processes that provide derived information to a user (such as reports, messages, or prompts) or other system.
Ex process that calculated average salary of all employees
Internal Logical Files (ILF)
Logical groupings of data maintained by the product
Ex. file, or table of employee records
External Interface Files (EIF)
Logical groupings of data that are external to the product (not maintained by product) but are used or referenced by product
Ex. file or table used by multiple products that maps machine-readable codes to human0readable descriptions
Scale used to answer questions 0 (not important) to 5 (essential) 14 questions total
Likert scale
What does M(md) stand for in equation
measure of difficulty
W(md)
weighting factor for measure m of difficulty d
V(q)
Value adjustment factor for question q
F
Number of function points
COSMIC functional measure
counts data movements associated with functional processes thar are initated as a result of trugger events.
Roetzheim version of function points
Used for Web Aps
Boehm
uses object points rather than function points (screens in user interface, reports and components/modules)
Person-month
Traditional effort estimate unit, amount of effort a typical developer expended in one month of work. (month is 4 and a half weeks)
person month has about 22 person days
effort estimates include
ally life cycle work : writing requirements and designs doing testing generating documents collecting data managing project ect
E = a + BF
what do symbols mean
E - denotes the effort (in person months)
F - denotes the size in function points
a and B are constants depending on Albrecht and Gafney or Kemerer model
Best for small products
E = aL^B
L is number of thousands of lines of code (KLOC)
B< 1 the project exhibits economics of scale (rare)
B> 1 exhibits diseconomies of scale
Watson and Felix
Basili and Preburgere
Boehm
What are diseconomies of scale examples
Communication problems and integration problems
E = a * F^B * N^Y
F is product size in function points
N max size of team
International Software Benchmarking Standards Group
Constructive Cost Model
One of the most complicated models developed by Boehm COCOMO
Use size measured in either lines of code or functional measures can convert from functional measures to LOC
B is the diseconomics of scale (increase rt to left)
W - effort multipliers (increase left to rt)
Do planners estimate the software size is Scrum?
No they usually just estimate effort for stories and tasks
What are effort estimates in scrum called?
story days or person month (ideal days or ideal months)
or story point
Story point/task point
A relative unit of size. These estimates are made by choosing one or a few small stories or tasks of about the same size and using them as a baseline (by declaring them to be of size one).
All stories or tasks are estimated relative to thi standard.
Effort estimates become more or less detailed over time
more detailed and more accurate
The Scrum estimate process has what advantage?
It avoids much work and rework on making effort estimates
Fallback to Scrum estimation process
Can not accurately estimate the release of a product
Planning poker
Technique for an agile team to come to consensus on effort estimates (Fibonacci sequence)
Who participates in planning poker
PO and SM but only team embers actually make estimates
PO presents explains and clarifies PBIs when questioned about them during planning poker, records story estimate
SM facilitates participation
