Chapter 5 Software Effort Estimation

Chap. 5 Software Eort Estimate From Bob Hughes Hughes,, Mike Cotterell, Rajib Mall 5th eitio! S"M

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#! time, withi! buget a! with the re$uire $ualit% Estimate eort with &osts a! a&ti'it% uratio!.

(here are estimates o!e •

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Strategi& "la!!i!g Feasibilit% stu% S%stem spe&i)&atio! E'aluatio! of suppliers proposal "roje&t pla!!i!g

"roblems with #'er a! *!er estimates •

#'erestimate+ ma% &ause the proje&t to take lo!ger tha! it woul otherwise  –

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"arki!so!s -aw+ (ork epa!s to )ll the time a'ailable Brooks -aw+ "utti!g more people o! a late job makes it better

Basis for Software Estimatio! •

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 /he !ee for histori&al 0ata + base o! past eperie!&e Measure of (ork+  –

S-#C1Sour&e -i!es of Coe2 •

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3o pre&ise e)!itio! 0i4&ult to estimate at start of the proje&t #!l% a &oe measure1!ot eort2 "rogrammer epe!e!t 0oes !ot &o!sier &oe &ompleit%

F"1Fu!&tio! "oi!t2

Software Estimatio!  /e&h!i$ues •

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lgorithmi& Moels+ 1Eort 2 Epert 6ugme!t !alog% "arki!so!s+ Sta eort a'ailable to o the1S&ope2 proje&t "ri&e to (i!+ "rei&t to 1"ri&e2&ost re$uire.  /op ow!+ #'erall estimate is broke! ow! o!to eort re$uire for &ompo!e!t tasks Bottom7up+ Compo!e!t tasks a! i!i'iual estimates are aggregate

 pro&eural &oe orie!te approa&h •

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Bottom up approa&h "rei&t the !umber a! t%pe of software moules i! the )!al s%stem Estimate the S-#C for ea&h moule Estimate the work1&ompleit% a!  /e&h!i&al i4&ult%2 Cal&ulate the work a%s eort+ Co!'ert S-#C to eort

 /op 0ow! pproa&h a! "arametri&1logorithmi&2 Moels •

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"arametri& Moel Eg+ 8!sura!&e to &o'er or rebuil the propert%, &ompa!% gi'es parameters base o! !o of stories, bri&ks b% la%er, &arpe!ter eort et&+ Eort 9 1S%stem Si:e2;1"rou&ti'it% rate2 <-#C1/housa!s of li!es=&oe2

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Eg+  is eperie!&e ,>? a%s=@<-#C  /herefore he re$. A? a%s for  <-#C B is less eperie!&es a! takes 55=<-#C  /herefore re$. 55;9@@? a%s to &oe <-#C "rou&ti'it%9 Eort=Si:e Eort 9 Co!st@1Si:e;Co!sta!t2

lber&ht Fu!&tio! "oi!t !al%sis •

5 major Compo!e!ts1Eter!al /%pes2  –

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Eter!al 8!put /%pes+ tra!sa&tio!s whi&h upate i!ter!al &omputer )le Eter!al #utput /%pes+ "ri!ts ,0ispla%s Eter!al 8!$uir% /%pes+ 3o upate o!lu ispla% 8!fo -ogi&al 8!ter!al Files Eter!al 8!terfa&e+ File t%pes allow for 8!put a! #utput

lbre&th &ompleit% Multiplier