University of Toronto Types of Inspection Benefits of Inspection Management reviews E g preliminary design review PDR critical design review CDR Used to provide confidence that the design is sound Attended by management and sponsors customers Often just a dog and pony show Inspection is more cost effective than testing Walkthroughs how to structure it Some tips 1 University of Toronto their their formality formality informal informal meetings meetingsover overcoffee coffee regular regularteam teammeetings meetings etc etc formal formal scheduled scheduledmeetings meetings prepared preparedparticipants participants defined definedagenda agenda specific specificformat format documented documentedoutput output 2 University of Toronto Department of Computer Science Department of Computer Science Inspection Constraints Source Adapted from Blum 1992 pp369 373 Freedman and Weinberg 1990 Formal inspection works well for programming Size enough people so that all the relevant expertise is available For applications programming more effective than testing most reviewed programs run correctly first time compare 10 50 attempts for test debug approach Duration Fagan recommends rates 130 150 SLOC per hour never more than 2 hours error reduction by a factor of 5 10 in some reported cases improvement in productivity 14 to 25 percentage of errors found by inspection 58 to 82 cost reduction of 50 80 for V V even including cost of inspection Outputs not too soon product not ready find problems the author is already aware of all reviewers must agree on the result increased morale reduced turnover better estimation and scheduling more knowledge about defect profiles better management recognition of staff ability not too late accept or re work or re inspect product in use errors are now very costly to fix all findings should be documented summary report for management detailed list of issues These benefits also apply to requirements inspections Timing Examines a product once its author has finished it concentration will flag if longer Effects on staff competence Scope focus on small part of a design not the whole thing min 3 4 if author is present max 7 less if leader is inexperienced Data from large projects Purpose Remember the biggest gains come from fixing the process Many empirical studies investigated variant inspection processes collect data to help you not to make the same errors next time Mixed results on the relative benefits of different processes Easterbrook 2004 Formal FormalTechnical TechnicalReviews Reviews FTRs FTRs Formal FormalInspections Inspections Easterbrook 2004 Source Adapted from Blum 1992 Freedman and Weinberg 1990 notes from Philip Johnson Other Other terms terms used used Fagan Inspections Benefits of formal inspection not not widely widely agreed agreed a process management tool always formal used to improve quality of the development process collect defect data to analyze the quality of the process written output is important major role in training junior staff and transferring expertise Easterbrook 2004 These These definitions definitions are are All All types types can can vary vary in in developer technique usually informal used by development teams to improve quality of product focus is on finding defects How to conduct an inspection who to invite Department of Computer Science Reviews Walkthroughs Inspections Lecture 6 Formal Inspections University of Toronto Department of Computer Science 3 Easterbrook 2004 4 1 University of Toronto University of Toronto Department of Computer Science Choosing Reviewers Roles Source Adapted from Freedman and Weinberg 1990 Source Adapted from Blum 1992 pp369 373 Formal Walkthrough Possibilities specialists in reviewing e g QA people people from the same team as the author people invited for specialist expertise people with an interest in the product people from other parts of the organization Exclude anyone with known personality clashes with other reviewers anyone who is not qualified to contribute anyone whose presence creates a conflict of interest 5 Easterbrook 2004 University of Toronto Department of Computer Science must be a competent programmer should be specially trained keeps review focussed could be from another project Recorder Designer programmer who produced the design being inspected Reader Author Coder Implementor programmer responsible for translating the design to code Tester person responsible for writing executing test cases Other Reviewers task is to find and report issues 6 Easterbrook 2004 University of Toronto Department of Computer Science Guidelines Opening Moments Source Adapted from Freedman and Weinberg 1990 Source Adapted from Wiegers 2001 Prior to the review 1 Don t start until everyone is present schedule Formal Reviews into the project planning 2 Leader announces train all reviewers We are here to review product X for purpose Y ensure all attendees prepare in advance 3 Leader introduces the reviewers and explains the recording technique During the review review the product not its author keep comments constructive professional and task focussed 4 Leader briefly reviews the materials stick to the agenda check that everyone received them check that everyone prepared leader must prevent drift limit debate and rebuttal record issues for later discussion resolution 5 Leader explains the type of review identify problems but don t try to solve them take written notes Note The review should not go ahead if After the review some reviewers are missing some reviewers didn t receive the materials some reviewers didn t prepare review the review process Easterbrook 2004 Moderator ensures preparation is done should actively participate may be the reader all management chairs the meeting summarizes the product piece by piece during the review i e line manager appraiser etc Review Leader keeps track of issues raised anyone responsible for reviewing the author Fagan Inspection reports the results visitors who have something to contribute Department of Computer Science 7 Easterbrook 2004 8 2 University of Toronto Department of Computer Science University of Toronto Structuring the inspection Department of Computer Science Fagan Inspection Process Source Adapted from Blum 1992 pp374 375 1 Overview Checklist review structured by issue on the list circulate materials Walkthough All participants perform individually review materials to detect defects Round Robin Rate 100 125 SLOC per hour each reviewer in turn gets to
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