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MELJUN CORTES SAD ch05

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MELJUN CORTES SAD ch05

MELJUN CORTES SAD ch05


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  • 1. Chapter 5Information Gathering:Unobtrusive Methods Systems Analysis and DesignMELJUN CORTES
  • 2. Major Topics • Sampling • Quantitative document analysis • Qualitative document analysis • Observation • STROBE • Applying STROBEKendall & © 2005 PearsonKendall Prentice Hall 5-2
  • 3. Sampling • Sampling is a process of systematically selecting representative elements of a population. • Involves two key decisions: • Which of the key documents and Web sites should be sampled. • Which people should be interviewed or sent questionnaires.Kendall & © 2005 PearsonKendall Prentice Hall 5-3
  • 4. Need for Sampling The reasons systems analysts do sampling are: • Reducing costs. • Speeding up the data-gathering process. • Improving effectiveness. • Reducing data-gathering bias.Kendall & © 2005 PearsonKendall Prentice Hall 5-4
  • 5. Sampling Design Steps To design a good sample, a systems analyst needs to follow four steps: • Determining the data to be collected or described. • Determining the population to be sampled. • Choosing the type of sample. • Deciding on the sample size.Kendall & © 2005 PearsonKendall Prentice Hall 5-5
  • 6. Sample Size The sample size decision should be made according to the specific conditions under which a systems analysts works with such as: • Sampling data on attributes. • Sampling data on variables. • Sampling qualitative data.Kendall & © 2005 PearsonKendall Prentice Hall 5-6
  • 7. Types of Sampling • The four types of sampling are: • Convenience. • Purposive. • Simple random. • Complex random.Kendall & © 2005 PearsonKendall Prentice Hall 5-7
  • 8. Convenience Sampling • Unrestricted, nonprobability samples • Easy to arrange • Most unreliableKendall & © 2005 PearsonKendall Prentice Hall 5-8
  • 9. Purposive Sampling • Based on judgment • Analyst chooses group of individuals to sample • Based on criteria • Nonprobability sample • Moderately reliableKendall & © 2005 PearsonKendall Prentice Hall 5-9
  • 10. Simple Random Sampling • Based on a numbered list of the population • Each person or document has an equal chance of being selectedKendall & © 2005 PearsonKendall Prentice Hall 5-10
  • 11. Complex Random Sampling • The three forms are: • Systematic sampling. • Stratified sampling. • Cluster sampling.Kendall & © 2005 PearsonKendall Prentice Hall 5-11
  • 12. Systematic Sampling • Simplest method of probability sampling • Choose every kth person on a list • Not good if the list is orderedKendall & © 2005 PearsonKendall Prentice Hall 5-12
  • 13. Stratified Sampling Stratification is the process of : • Identifying subpopulations or strata • Selecting objects or people for sampling from the subpopulation • Compensating for a disproportionate number of employees from a certain group • Selecting different methods to collect data from different subgroups. • Most important to the systems analystKendall & © 2005 PearsonKendall Prentice Hall 5-13
  • 14. Cluster Sampling • Select group of documents or people to study. • Select typical groups that represent the remaining ones.Kendall & © 2005 PearsonKendall Prentice Hall 5-14
  • 15. Deciding Sample Size forAttribute Data Steps to determine sample size are: • Determine the attribute to sample. • Locate the database or reports where the attribute is found. • Examine the attribute and estimate p, the proportion of the population having the attribute.Kendall & © 2005 PearsonKendall Prentice Hall 5-15
  • 16. Deciding Sample Size forAttribute Data Steps to determine sample size (continued) • Make the subjective decision regarding the acceptable interval estimate, i • Choose the confidence level and look up the confidence coefficient (z value) in a table • Calculate σp, the standard error of the proportion as follows: i σp = zKendall & © 2005 PearsonKendall Prentice Hall 5-16
  • 17. Deciding Sample Size forAttribute Data Steps to determine sample size (continued) • Determine the necessary sample size, n, using the following formula: p(1-p) n= +1 σp2Kendall & © 2005 PearsonKendall Prentice Hall 5-17
  • 18. Confidence Level Table 99% 2.58 98% 2.33 97% 2.17 96% 2.05 95% 1.96 90% 1.65 80% 1.28 50% .67Kendall & © 2005 PearsonKendall Prentice Hall 5-18
  • 19. Hard Data In addition to sampling, investigation of hard data is another effective method for systems analysts to gather information.Kendall & © 2005 PearsonKendall Prentice Hall 5-19
  • 20. Obtaining Hard Data Hard data can be obtained by: • Analyzing quantitative documents such as records used for decision making. • Performance reports. • Records. • Data capture forms. • Ecommerce and other transactions.Kendall & © 2005 PearsonKendall Prentice Hall 5-20
  • 21. Qualitative Documents Examine qualitative documents for the following: • Key or guiding metaphors. • Insiders vs. outsiders mentality. • What is considered good vs. evil. • Graphics, logos, and icons in common areas or Web pages. • A sense of humor.Kendall & © 2005 PearsonKendall Prentice Hall 5-21
  • 22. Analyzing QualitativeDocuments Qualitative documents include: • Memos. • Signs on bulletin boards. • Corporate Web sites. • Manuals. • Policy handbooks.Kendall & © 2005 PearsonKendall Prentice Hall 5-22
  • 23. Observation • Observation provides insight on what organizational members actually do. • See firsthand the relationships that exist between decision makers and other organizational members.Kendall & © 2005 PearsonKendall Prentice Hall 5-23
  • 24. Analyst’s Playscript • Involves observing the decision-makers behavior and recording their actions using a series of action verbs • Examples: • Talking. • Sampling. • Corresponding. • Deciding.Kendall & © 2005 PearsonKendall Prentice Hall 5-24
  • 25. STROBE STRuctured OBservation of the Environment-- a technique for observing the decision makers environmentKendall & © 2005 PearsonKendall Prentice Hall 5-25
  • 26. STROBE Elements Analyzes seven environmental elements: • Office location. • Desk placement. • Stationary equipment. • Props. • External information sources. • Office lighting and color. • Clothing worn by decision makers.Kendall & © 2005 PearsonKendall Prentice Hall 5-26
  • 27. Office Location • Accessible offices • Main corridors, open door • Major traffic flow area • Increase interaction frequency and informal messages • Inaccessible offices • May view the organization differently • Drift apart from Pearson in objectivesKendall & © 2005 othersKendall Prentice Hall 5-27
  • 28. Desk Placement • Visitors in a tight space, back to wall, large expanse behind desk • Indicates maximum power position • Desk facing the wall, chair at side • Encourages participation • Equal exchangesKendall & © 2005 PearsonKendall Prentice Hall 5-28
  • 29. Stationary Office Equipment File cabinets and bookshelves: • If not present, person stores few items of information personally. • If an abundance, person stores and values information.Kendall & © 2005 PearsonKendall Prentice Hall 5-29
  • 30. Props • Calculators • Personal computers • Pens, pencils, and rulers • If present, person processes data personallyKendall & © 2005 PearsonKendall Prentice Hall 5-30
  • 31. External Information Sources • Trade journals or newspapers indicate the person values outside information. • Company reports, memos, policy handbooks indicate the person values internal information.Kendall & © 2005 PearsonKendall Prentice Hall 5-31
  • 32. Office Lighting and Color • Warm, incandescent lighting indicates: • A tendency toward more personal communication. • More informal communication. • Brightly lit, bright colors indicate: • More formal communications (memos, reports).Kendall & © 2005 PearsonKendall Prentice Hall 5-32
  • 33. Clothing • Male • Formal two piece suit - maximum authority • Casual dressing (sport jacket/slacks) - more participative decision making • Female • Skirted suit - maximum authorityKendall & © 2005 PearsonKendall Prentice Hall 5-33
  • 34. Anecdotal List with Symbols • The five symbols used to evaluate how observation of the elements of STROBE compared with interview results are: • A checkmark, the narrative is confirmed. • An “X” means the narrative is reversed. • An oval or eye-shaped symbol serves as a cue to look further. • A square means observation modifies the narrative. • A circle means narrative is supplemented byKendall observation. 2005 Pearson & ©Kendall Prentice Hall 5-34