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![Delphi Estimating
a way of attempting to get specialists in predicting
software size to come to a consensus on their predictions -
important because experts often disagree.
How apply Delphi Technique ?
1. Group of experts [E1….Ei……En]
2. Meet to discuss project
3. Each estimates size:[X1….. Xi ….. Xn]
4. Each Ei __ gets to see all the Xs (anonymously)
5. Stop if the estimates are sufficiently close together
6. Otherwise, back to step 2
Wideband-Delphi Estimating
Delphi
Estimating is
?](https://image.slidesharecdn.com/9-ghulam-sabtain-ahmad-amin-160214060228/85/Software-Size-Estimation-24-320.jpg)
![Delphi Estimating
a way of attempting to get specialists in predicting
software size to come to a consensus on their predictions -
important because experts often disagree.
How apply Delphi Technique ?
1. Group of experts [E1….Ei……En]
2. Meet to discuss project
3. Each estimates size:[X1….. Xi ….. Xn]
4. Each Ei __ gets to see all the Xs (anonymously)
5. Stop if the estimates are sufficiently close together
6. Otherwise, back to step 2
Wideband-Delphi Estimating
Delphi
Estimating is
?](https://image.slidesharecdn.com/9-ghulam-sabtain-ahmad-amin-160214060228/75/Software-Size-Estimation-24-2048.jpg)
Uploaded byMuhammad Asim
Software Size Estimation
Software size estimation is a crucial activity in software engineering used to evaluate the size of applications or components, significantly impacting project cost estimation. It distinguishes between software sizing, which estimates size, and effort estimation, which predicts the effort required to build the software, utilizing methods such as functional size measurement and various estimation techniques including lines of code and function points. Understanding these techniques helps in accurate project planning and management through effective size measurement and estimation methodologies.
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Overview of software size estimation and its significance in project cost estimation.
Overview of software size estimation and its significance in project cost estimation.
Estimation stages include initial sizing, resizing during design changes, and final sizing after installation.
Illustrates the complexity experienced in accurately measuring software size.
Contrasts software sizing (size of software) with effort estimation (effort required to build it).
Details two measurement methods: Functional size measurement and Non-Functional size measurement.
Explains functional measurement methods, detailing advantages (repeatable) and disadvantages (requires experts).
Focuses on non-functional methods using technical objects like use-cases, DFDs, etc.
Outlines five estimation techniques: LOC, FP, Wideband Delphi, Component Estimating, 3-point Estimation.
Describes LOC types (Physical, Logical) and lists advantages and disadvantages associated with LOC.
Defines Function Points and outlines necessary steps for analysis and measurement.
Details the five components involved in Function Point analysis and their definitions.
Explains rating systems for transactional/data functions and how to calculate Final FP Count using GSC.
Lists benefits of using Function Points including agreement talks and historical comparison.
Introduces a three-step technique for estimating software size involving team collaboration.
Describes the Wideband Delphi method for consensus building among experts on software size estimation.
Explains the standard component estimation technique, utilizing historical data to predict size.
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Software Size Estimation
- 1.
- 3. Software Size Estimation Anactivity in software engineering that is used to estimate the size of a software application or component What is Software Size Estimation?
- 4. Size increases, theinterdependency among various elements of the software grows rapidly increase. “Software size is the main driver for project cost estimation” Why we feel need? Software Size Estimation
- 5. 1) Initial sizingduring or after requirements phase 2) Subsequent sizing after system design or when change occurs 3) Final sizing after install Define Design Build Test Implement Sizing Sizing Sizing When to Size Phases 1. Define 2. Design 3. Implement Software Size Estimation
- 6. The measurement ofsoftware size is hard. The Measurement of Software Size Why
- 7. Difference between Softwaresizing and software effort estimation? Sizing estimates the probable size of a piece of software while effort estimation predicts the effort needed to build it. Difference Software Sizing Vs Effort Estimation
- 8. The Measurement ofSoftware Size Two methods of software size measurement Functional size measurement method Non-Functional size measurement method. Method How?
- 9. Functional size measurementmethods Functional size measurement methods measure the functionality Advantages of functional size measurement methods The size measurement is repeatable and verifiable. The size measurement is defendable. Disadvantages of functional size measurement Need Expert People. It takes some time and costs effort Software Size Measurement Methods Functional Method (‘what does the software do’)
- 10. Non-functional size measurementmethods Measure the technical objects of the software e.g Use-Case , DFD, Sequence diagram etc. Software Size Measurement Methods Non- Functional Method ( Diagrams )
- 11. The Software Size Thereare many techniques of software size estimation but here we will discuss only five techniques which are : 1. LOC (Line of code) 2. Functional Point (FP) 3. Wideband Delphi 4. Component Estimating 5. 3-point Estimation
- 12. The Software SizingTechniques Types of LOC Two types of LOC 1) Physical LOC 2) Logical LOC Example 1. for (i = 0; i < 100; i++) printf("hello"); /* How many lines of code is this? */ 1. for (i = 0; i < 100; i++) { printf("hello"); } /* How many lines of code is this? */ LOC What is LOC ???
- 13. Advantages ofLOC 1. Automation of Counting 2. An Intuitive Metric Disadvantage of LOC 1. Lack of Accountability 2. Lack of Cohesion with Functionality 3. Developer’s Experience 4. Difference in Languages 5. Problems with Multiple Languages 6. Lack of Counting Standards. The Software Sizing Techniques LOC (Analysis)
- 14. The Software SizingTechniques An objective and structured technique to measure software size by quantifying its functionality provided to the user, based on the requirements and logical design. Function Point What is FP ?
- 15. Analysis Function Point The Software SizingTechniques Function point Analysis consists of performing the following steps: • Determine the type of Function Point count • Determine the application boundary • Identify and rate to the Unadjusted Function Point count (UFP) • Identify and rate the data function types to calculate their contribution to the UFP • Determine the Value Adjustment Factor (VAF) by using General System Characteristics (GSCs) • Finally, calculate the adjusted Function Point count
- 16. Component Function Point The Software SizingTechniques There are five component of FP: 1. EI’s (External Input) 2. EO’s (External output) 3. EQ’s (External inquiries) 4. EIF’s(External Interface Files) 5. ILF’s(Internal logical files)
- 17. Component Function Point The Software SizingTechniques 1. External Input (EI) Is an elementary process in which data crosses the boundary from outside to inside 2. External Output (EO) An elementary process in which derived data passes across the boundary from inside to outside 3. External Inquiry (EQ) Is an elementary process with both input and output components that results in data retrieval from one or more internal logical files and external interface files
- 18. Component Function Point The Software SizingTechniques 4. Internal Logical File (ILF) A user identifiable group of logically related data that resides entirely within the application boundary and is maintained through External Inputs 5. External Interface File (EIF) A user identifiable group of logically related data that is used for reference purposes only.
- 19. Rating the Transactionaland Data Function Types Each of the identified components is assigned a rating (as Low, Average, and High) General System Characteristics (GSCs) The value adjustment factor (VAF) is calculated based on General System Characteristics that rate the general functionality of the application being counted • Rating the Transaction • Data Functi0n Types Function Point The Software Sizing Techniques
- 20. The degree ofeffect of each characteristic has to be determined as a rating on a scale of 0 to 5 as defined below. 0: Not present, or no effect 1: Incidental effect 2: Moderate effect 3: Average effect 4: Significant effect 5: Strong effect throughout General System Characteristics (GSCs) Degree of Effect Characteristic
- 21. General System Characteristics(GSCs) Once all the GSCs have been rated, TDI is obtained by summing up all the ratings. Now, Value Adjustment Factor is calculated using the formula: VAF = 0.65 + TDI/100 Final FP Count FP = Unadjusted Function Point count (UFP) * Value Adjustment Factor (VAF) Total Degrees of Influence (TDI)
- 22. Advantages: 1. Helps Comparison 2.Helps Monitor Scope Creep 3. Ease of Agreement Talks 4. Use of Historic Data Advantages & Disadvantages Function Points
- 23. Three steps for estimatingthe software Point Estimation Technique The Software Sizing Techniques In this technique we examine the three steps for estimating the software. Step1: work with the team member assigned to each task to identify both the positive and negative risks involved in their task. Step2: we ask the team member to make three estimates 1. BG 2. P 3. O Step3: mathematics with the three estimates the weighted mean=(O + 4BG + P) ÷ 6 the standard deviation= (P-O)/6
- 24. Delphi Estimating a wayof attempting to get specialists in predicting software size to come to a consensus on their predictions - important because experts often disagree. How apply Delphi Technique ? 1. Group of experts [E1….Ei……En] 2. Meet to discuss project 3. Each estimates size:[X1….. Xi ….. Xn] 4. Each Ei __ gets to see all the Xs (anonymously) 5. Stop if the estimates are sufficiently close together 6. Otherwise, back to step 2 Wideband-Delphi Estimating Delphi Estimating is ?
- 25. Standard Component EstimationTechnique guess the size of a software system as a function of the size estimates of its components. Apply Method • Gather historical data on key components • Guess how many of each type you will need (Mi) • Also guess largest (Li)_ and smallest (Si)_ extremes • Final estimate (Ei_) is a function of Mi,Li and Si • For example Ei=(Si+(4*Mi)+Li)/6 How to Apply ?