The method is based on a comparison of like with like. Properties may be similar but each property is unique so that they can never be totally alike. As they move away from the ideal situation of absolute similarity, so the method becomes more unreliable. The reasons for dissimilarities are mainly:
(a) Location The position of any property is clearly unique. The actual position is an important factor in the value of a property and for some, such as shops, a major factor. For example, on an estate built to the same design at the same time, some houses will be nearer to a busy traffic road than others; some will be on higher ground with good views whilst others will be surrounded by other houses; some will back south, others back north; some will have larger plots than others. Even in a parade of shops some will be nearer a street crossing than others or be adjacent to a pedestrian exit from the car park or nearer to a popular large store.