Limited progress in converting manual systems to automated processes, Slides of Designs and Groups

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Model-Based Systems Analysis —

A Methodology and^ Case^ Study by John F. Rockart September 1969 Working Paper No.^ A15-

MASSACHUSETTS

50 MEMORIAL DRIVE

CAMBRIDGE. MASSACHUSETTS

SE? 151969

DEWEY LIBRARY

Model-Based Systems Analysis —

A Methodology and Case Study by John F. Rockart September 1969 Working^ Paper^ No.^ 415-

r]o, ^-, C.3.

RECFIVEO

M- SEPI- 18 1969

T. (^) LIBRARIES

More recently, Canning has pointed to the "painfully^ slow^ response"^ to management needs provided by the current techniques of systems analysis and design (3). Nor are these^ two^ alone^ in^ their^ comments.^ Words^ like "cumbersome tools" and "the tendency to simply^ copy^ the^ old^ system^ over into the new" sprinkle the great bulk of the literature^ on^ the^ subject. Today, most of the more common traditional programmed functions of^ bus- iness management, such as payroll and order^ entry,^ have^ been^ already^ trans- lated into computer processing. To handle new and^ less^ well^ understood functions, which^ are^ now^ of^ greater^ interest,^ the^ old^ techniques^ of^ systems analysis and design are sadly lacking. In^ order^ to^ effectively^ perform systems analysis and design in these newer areas, a new framework is necessary. In the area^ of^ systems^ design,^ model-based^ systems^ design^ as espoused by Carroll (5) and others appears to be one^ key^ to^ innovation^ and greater certainty of results in the fabrication of a new system. The step which precedes the design^ step^ in^ the^ data^ processing^ conver- sion process is, however, also in need of a new framework.^ It is^ this initial systems analysis^ step^ (sometimes^ referred^ to^ as^ the^ "systems study") with which this paper is concerned. After a discussion^ of^ exist- ing conventional systems analysis theory and tools, a three-pronged, model- based, systems analysis^ theory will^ be^ presented. First, let us pause to establish some definitions.^ In^ general,^ the process of converting from a manual system to an automated on has^ been divided into three steps, systems analysis, system design, and programming.

by Simon^ In^ the(4)^ sense^ of^ programmed^ versus^ non-^ programmed^ functions^ as^ described

.

-3-

"Analysis ... is finding out what is to be done; design is finding^ out^ how it should^ be^ done;^ programming^ is^ making^ the^ specified^ system^ a^ reality."^ (6) The distinction, as performed^ in^ practice,^ is^ not^ as^ clear^ cut.^ "As^ we know, the people called systems analysts actually do some of the^ work called systems design and, in some cases, so do the programmers." (8) There is extensive interaction^ between^ phases^ of^ the^ process.^ However,^ the^ analysis function, no matter when performed, is clear. It "is restricted to fact- finding and to examining systems to learn how they work ..."^ (8)

Conventional Systems^ Analysis Conventional systems analysis is described in varying^ ways^ by^ different authors. (^) (9, 10, 11, 12, 13) The process, however, is in general agreed upon by most as a series of steps dominated by interviews of operating personnel and data collection in the area to be studied. Typical of these formulations is^ a^ five-step^ program^ for^ the^ system^ analyst^ presented^ by

Gregory and Van Home. They suggest that the systems analyst should:

"First, obtain facts by interviewing people and observing activities timing-- that about lead^ theto^ events--theirthe origination^ type, of documents,volume,^ and main- tenance done at ofeach files, work issuancestation, ofand reports,flow of processingdocuments betweensteps stations

.

"Second, collect sample^ copies^ of^ filled-in^ documents,^ ..." "Third, every document study processingthat each operationsperson receives to learn or issues..."the how and why of "Fourth, organize the facts obtained into flow charts, flow origin,^ lists^ or throughother^ suitableeach stage^ form of^ tocommunication^ trace^ the^ path and^ ofprocessing,^ data^ from into files, and out of files to reports. "Fifth, interview each user of documents and reports to learn what needs." information (14) he^ uses^ in^ his^ work^ and^ what^ he^ thinks^ he

Exhibit 1 Input-Output Chart

ORDER processing^ Input^ and FOR^ outputSTOCK^ ITEMSof^ customer ^SEMSm

TBI

1=^^

Information^ Reproduced Systems,"^ from^ Evans,Harvard^ M. Business^ K.^ and^ Hague,Review^ , L.Jan-Feb^ R.^ ,^ "Master^ 1962, Planp. 98.^ for

The use^ of^ I/O^ charts^ leads^ to^ an^ identification^ of^ the^ significant^ data items in the particular system being analyzed.^ It^ allows^ the^ elimination^ of redundant data item inputs. Finally, it focuses attention on often-used per- manent types of^ information^ which^ should^ be^ stored^ on^ a^ master^ file.^ (17) A. Statistical Sampling Techniques^.^ It^ has^ long^ been^ recognized^ that^ a relatively few well-chosen observations will permit inferences to be drawn re- garding the total population^ from^ which^ the^ sample^ was^ drawn.^ In^ order^ to reduce system study costs, these techniques^ have^ necessarily^ been^ utilized.

5. Estimating. As a last resort, where the above techniques have been unsuccessful in gathering^ data,^ the^ analyst^ often^ has^ turned^ to^ his^ data

gathering tool of last resort —estimating. Not much is written about this

tool, but it is often used.

Data Presentation Techniques

6. Systems Flow Charts. Two techniques are used by systems analysts to describe the logical flow of the procedures that have been studied. The first, and most widespread, is the technique of flow charting. Exhibit^2 shows^ a typical flow chart of a procedure. Included are the most ubiquitous symbols, the rectangle for procedure steps, and the diamond^ for^ decision^ points.^ Ap- proximately a dozen other symbols are in common use, the majority representing different types of storage media.
7. Decision Tables. The other major^ technique^ utilized^ by^ systems analysts to exhibit procedural flows is the decision table. Shown^ in^ Exhibit 3, a sample decision table illustrates, in^ a^ more^ compact^ form,^ the^ logic from the flow chart which was presented in Exhibit 2. The popularity of decision tables is due to three factors. They are