Researchers from a variety of disciplines have studied Quality Of Life (QOL) since the 1930s (53). They tried to identify the components of QOL and compared various geographical areas such as cities, states and nations by means of QOL indices that they developed (2), (3), (25), (48), (47). In addition to the researchers, international organizations such as UNDP (51) developed its own measures for QOL. The desire to improve the quality of life in a particular place or for a particular person or group is an important focus of attention for planners (28).
An important reason for such an interest in QOL lies in the question of effective allocation of scarce resources (32). In fact improvement of life quality in each society is one of the important aims of public policies. In recent years studies of life quality have mainly concentrated on the urban nature and urban quality of life gained much attention among the researchers. Clearly the increase of urban population and the increasing tendency for living in the city is one of the main incentives to expand an independent movement on life quality researches.
The urban QOL concept gains more importance when it is considered that the world population is expected to reach somewhere between 7.6-9.4 billion (22) and the urban population is expected to reach 50% (47) in the beginning of the next century. The multi-dimensional character and evolutional nature of quality of life led to different interpretations which made the investigation difficult. So the recent research on the quality of life emphasis on the quality of measuring this concept in the cities. Clark and Kahn (7) used a two-stage hedonic approach to estimate willingness to pay for urban cultural amenities such as muse ums, theater, dance, instrumental music and zoos. For a typical city, the marginal benefits from improving these cultural goods are estimated to be in the $.85-$57.9 mil lion range for an additional theater and an additional zoo, respectively. Stover and Leven (48) examined the importance of functional form in estimating values for the quality of life in urban areas. Values of local amenities are assessed from the interaction between the labor and real estate markets. Alternative theoretical specifications are consistent with previous study but yet different. Results show quality of life rankings for 253 urban counties are highly sensitive to alter native model specifications.
In Giannias (16) research, a structural approach to hedonic equilibrium models is used to estimate a quality of life ranking of five cities in the United States. Quality of life is a function of housing and neighborhood characteristics (number of rooms, air quality and travel time to work) and of city-wide amenities. Resulting quality of life values and rankings are different from those implied by previous study. Michalos and Zumbo (33) predicted life satisfaction from 14 life domains for seven different time periods between 1979 and 1997. Of those domains relating to urban QOL, housing was significant in six time Objective and subjective indicators of urban quality of life 81 periods, recreational activity in five, transportation in four, government services in three and residential area in two (though it was not included in one time period). Thus, satisfactions in various urban domains predict overall life satisfaction.
Ulengin et al. (50) used a multidimensional approach to urban quality of life. The purpose of this study is to model the priorities, expectations and needs of the inhabitants of Istanbul, a city with a population of about 10 million, from a multidimensional perspective. In this way, effective allocation of the city's resources can be achieved to improve the Quality Of Life (QOL) for such a large number of people, which is the primary concern of the local authorities as well as the urban planners. For this reason, a survey is conducted in Istanbul so that the priorities of the inhabitants are revealed and the city where they would like to live is portrayed. The data obtained are used as input for hierarchical conjoint analysis. The survey is primarily based on the evaluation of hypothetical, experimentally designed city profiles for four different constructs on a 0-10 rating scale. The relative importance of the constructs is estimated through the eigenvector approach.
McCrea et al. (30) examined different geographic levels of subjective urban QOL. Regional satisfaction was best predicted by evaluations of regional services (such as health and education) and the cost of living, while evaluations of environmental and urban growth problems were significant predictors of regional satisfaction for younger persons. Neighborhood satisfaction was best predicted by evaluations of social interactions, neighborhood crime and public facilities (parks, libraries), while housing satisfaction was predicted best by age of home and home ownership. Richards et al. (39) investigate the factors that are most important in improving the quality of life of residents in informal housing as well as the main obstacles to a better quality of life. It uses regression analysis to obtain an understanding of the kinds of issues which shape quality of life in these areas and concludes by suggesting several research directions which would improve our knowledge of quality of life for informal settlement residents.
The present study attempts to provide an appropriate framework by using analytic hierarchical process for objective measuring of urban quality of life. Then it will conduct a comparative study in two urban centers of Iran. Such study not only provides a good context for measuring quality of life but it facilitates the participation of urban authorities and local decision makers to take part in the process of planning.
Measuring quality of life: A number of researchers such as Mc Call (29), Mayers (35), Davidson and Cotter (10), O'Brien and Ayidya (36), Grayson and Young (17), Diener and Suh (12), Turksever and Atalik (49) have reviewed literature on QOL and there is general agreement that a meaningful definition of QOL must recognize that there are two linked dimensions to the concept, namely a psychological one and an environmental one. Dissart and Deller (13) argue that "A person's quality of life is dependent on the exogenous (objective) facts of his or her life and the endogenous (subjective) perceptions he or she has of these factors and of himself or herself." Grayson and Young (17) note that "there appears to be a consensus that in defining quality of life there are two fundamental sets of components and processes operating: those that relate to an internal psychological mechanism producing a sense of satisfaction or gratification with life and those external conditions which trigger the internal mechanism."
With respect to the first dimension other terms have been used, for example individual/ personal QOL, subjective well-being or life satisfaction. For the second dimension there are different levels and terms used for example urban QOL, community QOL, quality of place, environmental QOL (28). Since the concept of 'quality of life' is very complex, often it is said that integrating the two dimensions can provide a good picture of quality of life for a person or a place. Dissart and Deller (13) reasoning that "quality of life for an individual is depended to the objective and external realities and his (her) subjective and internal perception of these factors and himself too." As noted already the concept of quality of life is complex and it could be used in the field of urban planning when an appropriate and reliable framework is devised for measuring it.
There are two sets of indicators for the measuring quality of life which most of the researchers are agreed with them. The first set is Objective Indicators which refers to the objective and visible aspects of the urban life and are defined by different elements. For example the number of hospitals in a city, unemployment rate, the volume of crime and the area of urban green spaces. The second set is Subjective Indicators which tries to measure and quantify the citizens' satisfaction from the urban welfare. For instance satisfaction of people from health care accessibility, access to job, satisfaction of urban security or access to green spaces.
There are two main approaches for measuring urban quality of life in the literature which is accepted by the most of the researchers. First one is Objective Urban Quality of Life and the second approach is Subjective Urban Quality of Life. However the citizen satisfaction from different aspects of urban life would not be study by this approach but the objective indicators are measured. In this approach the secondary data are used for indicator definition and is depended to the different statistics of the city in some extend. Objective urban QOL studies typically include many objective characteristics of the urban environment, often combining or weighting objective indicators to generate an objective urban QOL ranking for places (2), (3), (6), (43), (48), (50).
Studies on subjective urban QOL have found that subjective evaluations of many aspects of the urban environment can contribute to satisfaction in urban domains and overall life satisfaction (30), (33), (45), (46), (49). The urban quality of life is measured by using the subjective indicators and instead of secondary data, the citizens are asked (questionnaires, interview ...) directly for the level of their happiness about different aspects of urban life. Measuring subjective indicators are more time consuming and costly, however the results are more logic and real than the first approach.
Empirical research provides support for the generalization that correlations between objective indicators and relevant life satisfaction domains are often weak and generally lower than correlations between life...