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Before any system for improving agricultural management can be developed, a specific structure or strategy should be applied to aid the development process. There is no single approach used for the development of DSSs. Decision making strategies used by individuals vary with the amount of information they are presented with and with the sequence in which they obtain it. The process is also affected by the amount of pressure that the farmers are under to reach a decision, for example due to time or importance of the outcomes.

Using agriculture as a reference point, there are three types of in-farm management decisions that need to be considered.

1. Operational decisions 2. Tactical decisions 3. Strategic decisions

Operational and tactical decisions tend to be ‘actions’, while strategic decisions tend to be related to ‘planning’ (France et al, 1984; Kourik, 1986; Matthews, 2000 and 2002).

There are also three levels of farm system that have been identified that relate to the type of modelling approach used (Tsuji et al, 1998; Matthews et al, 2002).

1. Unconstrained – models that focus on the ecological components only

2. Resource constrained – models that incorporate the economic components in addition to the unconstrained level. They may include simple decision-making processes

3. Adaptive – models which incorporate the social component in addition to the resource constrained level

For the production of the Tanzanian DSS the system based upon the adaptive approach will be utilised – this looks at resource capture and utilisation by crops, along with social factors.

To develop a robust and applicable DSS a logical structure is required that is transparent and an approach that is amenable to subsequent improvements. Various strategies and frameworks are presented in the literature – e.g. the Systems Development Cycle (Anon, 1988b) and those expressed by Marakas (1998 and 2003) e.g. Simon’s model (Simon, 1960) – both of which have similar characteristics in terms of application.

The following examples of development processes highlight the common similarities.

In summary, the processes have a start point that involves the analysis of existing methods. This is followed by determining new or improved management approaches, and finishes with the development and application of the new approaches. These simple stages are highlighted predominantly by the SHARES (SHAred RESources) approach as devised by Stroosnijder et al (2001).

Examples of decision support strategies include:

• Systems development project management guide

• Marakas approach – phases of development

• Simon’s model

• SHARES approach

The methods above share common traits, which are summarised below. An aim of this project is to use elements of these approaches to formulate a single and more generic strategy for the development of decision support systems.

The Systems Development Project Management Guide (Anon, 1988) provides a generic framework for the development of decision support systems. (See Figure 3.1).

Figure 3.1: Framework for the development of DSSs (Anon, 1988)

The development of the DSS should follow a structured development ‘life cycle’. This is a further expansion of the above diagram and can be illustrated by Figure 3.2

Figure 3.2: Development life cycle for the production of a DSS (Anon, 1988b) Determine scope and

objectives

Analyse existing systems

Determine detailed requirements

Develop a new system

Test, update, implement and develop the system

Review the solution and propose changes

Problem Definition

Code generation Testing

Implementation Feasibility analysis

Systems analysis

Systems design

Maintenance

Decision-making is a structured process. Figure 3.3 demonstrates this.

Figure 3.3: Structured process of decision-making. (Adapted from Marakas, 1998 and 2003).

Simon’s model (Marakas, 2003) recognises that the user of the system has some understanding of the processes involved within the model and the purpose behind its use. There is an element of prior knowledge of the system from the user, such that they are able to discern whether or not the outcome from the model is feasible (Rizzoli et al, 1997). Elements of computer aided design (CAD) need to be applied to the design of the system to help ensure the user-interface of the DSS is suitable and workable. Areas of interest include the layout, text and graphics, and aesthetics – colour, style etc.

From the system, a series of solutions should be offered to allow the user the ability to choose the approach that they feel is best. This choice will occur before the implementation of any improved management strategy is undertaken. Before and after implementing a proposed strategy it is important to carry out a feasibility analysis on the approach. This will help in determining any modifications that are required. Then the decision-making process can start again.

The information stated above is illustrated in diagrammatical form in Figure 3.4.

Frame of

Figure 3.4: Simon’s model for DSS development adapted from Marakas (2003).

Simon’s model is a good example of an approach for DSS development that focuses on the application of quantitative methodologies, information and testing.

Qualitative researchers also possess approaches for the development of models and for determining management decisions. Although these methods follow a structured flow, some scientists deem them to be less structured than the quantitative approaches to modelling (Bryman, 2000), primarily due to the extensive interaction and questioning of the potential users of the system.

One example of DSS development used for qualitative research is that outlined by Stroosnijder (2001) under the title of SHARES. This method is split into three distinct parts:

1. Descriptive phase 2. Explorative phase 3. Planning phase

Each phase shall now be expanded upon stating the aim of the phase and the expected outcome.

Descriptive Phase

- Aim: Characterisation of present situation

- Output: A description of the present situation and potential solutions utilising existing technologies

Explorative Phase

- Aim: Explore medium term options for development

- Output: A structured matrix describing optima for various object functions

Planning Phase

- Aim: To analyse ways and means to bridge the gap between the present situation and potential solutions

- Expected Output: A clear indication of how this can actually be realised

SHARES approaches model development in a holistic fashion, while still remaining relatively simple. SHARES can serve as an intermediary tool between scientists and extension officers working in the field who have close relationships with the potential beneficiaries of any developed systems. Principally the approach used to instigate this model is linear programming as the model undergoes linear processes.

These examples of quantitative and qualitative approaches to modelling can now be discussed in relation to integrating them to form a single development strategy.