Fishbein Model: Evaluation vs Performance

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Introduction

The Fishbein multi-attribute attitude model (1963, 1975) is a foundational framework in consumer behavior and marketing research. It explains how attitudes toward a product or brand are formed as a weighted sum of beliefs about its attributes. The model is central in market research for understanding purchase intentions and brand positioning.

Fishbein proposed that a consumer's attitude is not a vague feeling, but rather a structured, measurable construct that can be decomposed into specific attribute-level evaluations and beliefs.



The Model

The attitude toward object \(o\) is defined as:

\[ A_o = \sum_{i=1}^{n} b_i \cdot e_i \]

Where:

The attitude is a weighted sum of beliefs weighted by evaluations. A higher \(A_o\) indicates a more favorable attitude toward the object.



Components Explained

Beliefs (\(b_i\))

Measured on a scale (e.g., 1–7) asking:

  • "How likely is it that brand X has attribute \(i\)?"
  • "How does brand X perform on attribute \(i\)?"

Beliefs represent the consumer's subjective perception of a brand's performance on each attribute.

Evaluations (\(e_i\))

Measured asking:

  • "How important/desirable is attribute \(i\)?"
  • "How good/bad is attribute \(i\)?"

Scale typically ranges from \(-3\) to \(+3\) or 1 to 7. Evaluations capture the importance or desirability of each attribute regardless of any specific brand.

Attitude (\(A_o\))

The overall favorability toward the object. A higher \(A_o\) indicates a more positive attitude. It aggregates all attribute-level judgments into a single summary measure.



Evaluation vs Performance Matrix (IPA)

Attributes can be plotted on a 2D space:

This produces four quadrants:

QuadrantImportancePerformanceLabelStrategy
IHighHighSTRENGTHSMaintain
IIHighLowWEAKNESSESImprove!
IIILowHighOVER-INVESTMENTReduce
IVLowLowLOW PRIORITYIgnore

This framework is also known as Importance-Performance Analysis (IPA), introduced by Martilla & James (1977). It provides a direct, actionable visualization for managerial decision-making.



Extended Fishbein Model (Theory of Reasoned Action)

The Theory of Reasoned Action (Fishbein & Ajzen, 1975) extends the basic model to predict behavioral intentions:

\[ BI = w_1 \cdot A_o + w_2 \cdot SN \]

Where:

The Subjective Norm is defined as:

\[ SN = \sum_{j=1}^{m} NB_j \cdot MC_j \]

Where:

The model predicts behavior through intentions, which are jointly determined by personal attitudes and perceived social pressure.



Practical Application

Steps to apply the Fishbein model in market research:

  1. Identify salient attributes through qualitative research (focus groups, interviews)
  2. Measure beliefs \(b_i\) for each brand on each attribute
  3. Measure evaluations \(e_i\) for each attribute (brand-independent)
  4. Compute \(A_o\) for each brand: \(A_o = \sum b_i \cdot e_i\)
  5. Compare brands — rank by total attitude score
  6. Identify improvement priorities via the IPA matrix (Evaluation vs Performance)


Strategies to Change Attitudes

Based on \(A_o = \sum_{i=1}^{n} b_i \cdot e_i\), a firm can improve its brand attitude through several strategies:



Limitations