PROTOTYPING: THE DSS DEVELOPMENT METHODOLOGY

6.5 PROTOTYPING: THE DSS DEVELOPMENT METHODOLOGY

Because of the semistructured or unstructured n a t u r e of p r o b l e m s addressed by deci- sion s u p p o r t systems, it is quite unlikely that m a n a g e r s a n d D S S d e v e l o p e r s h a v e a

c o m p l e t e u n d e r s t a n d i n g of t h e decision-making p r o b l e m . T h e y m a y n o t u n d e r s t a n d the scope of t h e p r o b l e m , t h e types of a p p r o p r i a t e m o d e l s or technologies to apply, and/or t h e i n f o r m a t i o n needs. S o most D S S are d e v e l o p e d t h r o u g h t h e p r o t o t y p i n g

process. P r o t o t y p i n g is also k n o w n as iterative design or evolutionary development.

(Other names are middle-out process, adaptive design, and incremental design.) The prototyping d e v e l o p m e n t m e t h o d o l o g y aims at building a D S S in a series of

short steps with immediate f e e d b a c k f r o m users to ensure that d e v e l o p m e n t is p r o c e e d - ing correctly. Therefore, D S S tools must be flexible to permit changes quickly and easily.

We show t h e details of t h e prototyping m e t h o d o l o g y in Figure 6.3. P r o t o t y p i n g is a process of building a "quick and dirty" version of a system. T h e evolutionary a p p r o a c h starts with overall D S S planning and some analysis. U s e r s and managers, as well as an executive sponsor, must be involved. O t h e r factors, critical for success or leading to failure are m e n t i o n e d in the O p e n i n g Vignette and several of t h e D S S in A c t i o n a n d

D S S in Focus boxes. Next, t h e analysis, design, a n d p r o t o t y p e i m p l e m e n t a t i o n p h a s e s a r e iteratively

p e r f o r m e d until a small p r o t o t y p e is sufficiently d e v e l o p e d (decided on jointly by t h e developers, managers, and users). T h e n the final i m p l e m e n t a t i o n of this part of t h e sys- t e m takes place. Simultaneously, f u r t h e r iterations occur in t h e loop of analysis-design- implementation-system p r o t o t y p e as other subsystems or capabilities are a d d e d to t h e deployed system until a fairly stable, c o m p r e h e n s i v e system evolves. This is h o w t h e systems in the O p e n i n g Vignette and in Case Application 6.1 w e r e developed.

T h e first m a j o r decision involves which s u b p r o b l e m to build first. T h e user and t h e

d e v e l o p e r jointly identify a s u b p r o b l e m for which the initial D S S p r o t o t y p e is to be implemented. This early joint effort sets up initial working relationships b e t w e e n t h e participants and opens t h e lines of communication. T h e s u b p r o b l e m should be small

e n o u g h that the n a t u r e of t h e p r o b l e m , the n e e d f o r computer-based support, a n d t h e n a t u r e of this s u p p o r t are clear or quickly established. It should be of high interest value to the decision-maker. In t h e O p e n i n g Vignette, it was t h e e m p l o y e e b e n e f i t s subsystem that provided intense visibility for t h e system b e c a u s e everyone used it. For Case Application 6.1, it was the small calcine plant and m o c k e d up versions of several r e p o r t s (See D S S in A c t i o n 6.2). This a p p r o a c h helps to excite m a n a g e r s a n d u s e r s

a b o u t the potential of t h e system they want.

A p r o t o t y p e is ideally a small but usable system for t h e decision-maker. No m a j o r

355 P A R T 11 DECISION SUPPORT SYSTEMS

t h r o u g h all t h e steps of t h e s y s t e m - d e v e l o p m e n t p r o c e s s quickly, t h o u g h on a small scale. T h e s y s t e m should, of necessity, be simple. As the s y s t e m evolves, it must be eval-

u a t e d continuously. At the e n d of e a c h cycle it is e v a l u a t e d by b o t h the user and t h e developer.

T h e interaction of user, d e v e l o p e r , and t e c h n o l o g y is e x t r e m e l y important in this process. There is a balance of effort and c o o p e r a t i o n b e t w e e n user and d e v e l o p e r : T h e user takes the l e a d in t h e use and evaluation activities, and t h e d e v e l o p e r is stronger in t h e design and i m p l e m e n t a t i o n phases. T h e user plays an active role, in contrast to the situation in c o n v e n t i o n a l s y s t e m d e v e l o p m e n t , w h e r e the user o f t e n o p e r a t e s in a reac- tive or passive role. N o t e that the specification of n e e d e d data or i n f o r m a t i o n e v o l v e s as t h e p r o t o t y p e e v o l v e s along with user and d e v e l o p e r e x p e r i e n c e .

As w a s described in C h a p t e r 2, d e c i s i o n - m a k e r s m u s t share a c o m m o n f r a m e in o r d e r t o m a k e i n t e l l i g e n t d e c i s i o n s . M c C a r t h y and M c C a r t h y ( 2 0 0 2 ) a d v o c a t e that m a n a g i n g a t e c h n o l o g y d e v e l o p m e n t g r o u p requires setting such a shared vision of a project and setting the rules for h o w t e a m m e m b e r s are to work together. M a l h o t r a et al. (2001) describe h o w a flexible g r o u p support s y s t e m w a s c o n t i n u o u s l y m o d i f i e d to support a n e n g i n e e r i n g product design team. T h e G S S d e v e l o p m e n t t e a m was e v e n t u - ally required to attend t h e technical s e s s i o n s of the p r o d u c t d e s i g n g r o u p so that its m e m b e r s c o u l d gain first-hand k n o w l e d g e o f h o w t h e s y s t e m w a s b e i n g used, and h o w the design group w a n t e d it to be m o d i f i e d — t h a t is, to share the vision with t h e users. S y s t e m d e v e l o p m e n t t e a m s are o f t e n scattered around the globe, s o m e t i m e s w o r k i n g

f o r o t h e r c o m p a n i e s . T h e n e e d f o r e n h a n c e d c o l l a b o r a t i o n a n d t e a m w o r k i s para- m o u n t . T h e vision is not only to build better t e a m s by leveraging the best m i n d s and

c o m m o n tools, but also to potentially bring c u s t o m e r s into d e v e l o p m e n t . Project m a n -

a g e m e n t e n g a g e m e n t s are m o v i n g to a higher level of interactivity, requiring collabo- r a t i o n m a n a g e m e n t ( s e e J o h n s o n , 2 0 0 1 ) . G S S c a n assist s o f t w a r e d e v e l o p e r s . N e w . C A S E t o o l s include collaborative software; for e x a m p l e , C o l l a b N e t S o u r c e C a s t ( W e b -

b a s e d ) , V A Software, and Q u o v i x . T h e s e W e b - b a s e d s y s t e m s track s o f t w a r e versions, provide online collaboration, and a repository ( s e e Fry, 2002).

E v a l u a t i o n is an integral part of the d e v e l o p m e n t p r o c e s s and is t h e control m e c h - anism for the entire iterative desig n process. T h e e v a l u a t i o n m e c h a n i s m is w h a t k e e p s t h e cost and effort of d e v e l o p i n g a D S S consistent with its value. At the e n d of t h e e v o -

lution, a d e c i s i o n is m a d e on w h e t h e r to further r e f i n e the D S S or to stop. If the prototype is OK, we move to formal implementation of the DSS, which

c o u l d include all the user training, and so on. S u b s e q u e n t cycles e x p a n d and i m p r o v e the original version of the D S S . A l l the analysis, design, construction, i m p l e m e n t a t i o n , and evaluation steps are r e p e a t e d in e a c h successive r e f i n e m e n t .

Years ago, under the traditional S D L C , the analyst o b t a i n e d i n f o r m a t i o n require- m e n t s and o t h e r data f r o m the user and w e n t a w a y for a l o n g p e r i o d of t i m e to d e v e l o p

a system. O v e r time, the business e n v i r o n m e n t , the organization, the users' needs, and

e v e n the users might change. W h e n the s y s t e m w a s delivered, it m i g h t not m e e t any- o n e ' s needs, or the c h a m p i o n m a y h a v e left the organization (for an excellen t e x a m p l e of this situation, s e e Vedder, Van D y k e , and Prybutok, 2 0 0 2 ) . In prototyping, l o o p i n g back to early stages implies that the initial analysis w a s i n c o m p l e t e , as is e x p e c t e d .

T h e iterative design approach p r o d u c e s a specific D S S application. T h e p r o c e s s is fairly straightforward for a D S S d e s i g n e d for personal support. T h e p r o c e s s b e c o m e s m o r e c o m p l i c a t e d , a l t h o u g h n o t invalid, f o r a D S S that p r o v i d e s g r o u p s u p p o r t o r organizational support. Specifically, there is a greater n e e d for m e c h a n i s m s to support

c o m m u n i c a t i o n a m o n g users and developers. T h e r e is also a n e e d for m e c h a n i s m s to

C H A P T E R 6 DECISION SUPPORT SYSTEM DEVELOPMENT

M o s t D S S a n d W e b sites a r e d e v e l o p e d w i t h t h e p r o t o t y p i n g m e t h o d o l o g y . O n e r e a s o n is t h a t p r o t o t y p i n g allows t h e d e v e l o p e r s to get a u s a b l e ( p e r h a p s p a r t i a l ) sys- t e m u p a n d r u n n i n g relatively fast. A n d i f o n e views D S S a n d W e b sites a s n e v e r c o m - plete, b u t always in a s t a t e of e v o l u t i o n , p r o t o t y p i n g is an i d e a l m e t h o d o l o g y (see D S S

i n F o c u s 6.18). S o m e p r o t o t y p i n g o f n o n - D S S i s p e r f o r m e d w i t h t h e s a m e s o f t w a r e p a c k a g e s with w h i c h t h e D S S i s d e v e l o p e d , i n c l u d i n g D S S g e n e r a t o r s a n d D S S t o o l s like r e p o r t g e n e r a t o r s , G U I g e n e r a t o r s , a n d s p r e a d s h e e t s . A n a p p l i c a t i o n g e n e r a t o r i s o f t e n n o t h i n g m o r e t h a n a collection of p r o t o t y p i n g t o o l s t h a t e n a b l e s a full r a n g e of s y s t e m d e v e l o p m e n t activities a n d is v e r y similar to a D S S g e n e r a t o r .

Specifically, D S S d e v e l o p m e n t i s d o n e t h r o u g h p r o t o t y p i n g f o r t h e f o l l o w i n g r e a - sons:

• Users and managers are involved in every phase and iteration. The iterative nature allows u s e r s t o b e i n v o l v e d i n s y s t e m design, w h i c h i s i m p o r t a n t f o r D S S . T h i s approach stems froma need for user expertise in the design and recognizes that successful i m p l e m e n t a t i o n i s m o r e easily a c h i e v e d with active i n v o l v e m e n t . S o m e t i m e s this i n v o l v e m e n t is called t h e joint application development (JAD) method.

• Learning is explicitly integrated into the design process. Since the users are involved i n s y s t e m design, b o t h u s e r s a n d s y s t e m d e v e l o p e r s l e a r n a b o u t t h e

d e c i s i o n - m a k i n g , t h e ill-structured, c o m p l e x p r o b l e m , a n d t h e t e c h n o l o g i e s t h a t

c a n p o t e n t i a l l y b e a p p l i e d t o it.

• Prototyping essentially bypasses the formal life-cycle substep 7—information r e q u i r e m e n t d e f i n i t i o n ( s e e T a b l e 6.1). R e q u i r e m e n t s e v o l v e a s e x p e r i e n c e i s gained. This s t r a t e g y a s s u m e s t h a t t h e r e q u i r e m e n t s a r e only partially k n o w n a t t h e b e g i n n i n g o f s y s t e m d e v e l o p m e n t , a n d i t a t t e m p t s t o clarify u s e r s ' n e e d s b y actively involving t h e m in a low-cost, f a s t - f e e d b a c k d e v e l o p m e n t process.

• A key criterion associated with prototyping is the short interval between iterations. T h e f e e d b a c k m u s t b e fast. This c r i t e r i o n r e s u l t s f r o m t h e r e q u i r e d l e a r n i n g p r o c e s s : A c c u r a t e a n d t i m e l y f e e d b a c k is a p r e r e q u i s i t e to e f f e c t i v e l e a r n i n g .

• The initial prototype must be low-cost. It m u s t fall b e l o w t h e m i n i m u m t h r e s h o l d of c a p i t a l o u t l a y s r e q u i r i n g f o r m a l j u s t i f i c a t i o n . T h e d e v e l o p m e n t of a p r o t o t y p e m a y be a risky decision, p a r t i c u l a r l y f o r a D S S . H o w e v e r , b e c a u s e t h e b e n e f i t s of

a D S S a r e o f t e n intangible, r e l a t i n g t o s u c h issues a s i m p r o v e d d e c i s i o n - m a k i n g o r

b e t t e r u n d e r s t a n d i n g , a high initial i n v e s t m e n t m a y r e s u l t in a d e c i s i o n n o t to p r o -

c e e d (see D S S i n F o c u s 6.14).

DSS I N FOCU S 6.18