The Relevance of Vertical Housing to the Socio-Economic Characteristics of Occupants in Semarang City, Indonesia: Particularly the Proximity of Public Facility Aspects

Population growth and economic development can lead to increased housing demand amid limitations and rising land prices in the City of Semarang, Indonesia. One effort to overcome this challenge has involved shifting the approach to providing shelter to building vertical housing. However, various problems have emerged which suggest that vertical housing is not currently relevant to the socio-economic characteristics of its inhabitants. Thus, this study aims to determine the relevance of vertical housing to residents’ socio-economic characteristics particularly in proximity of public facility aspects. To achieve the research objective, this research uses quantitative research method. Importance–performance analysis (IPA) uses to determine the relevance of vertical housing to residents’ socio-economic characteristics and geospasial tools use to analyze descriptively the proximity of public facilities. Based on the relevance analysis, it can be concluded that the relevance between residents in apartments and residents in flats has some differences. This could happen because of differences in the location and financial capability of residents in apartment and flat. Performance improvement is needed, especially on economic factors for apartments and accessibility factors for low-cost flats so that vertical housing can become more relevant. Therefore, these findings can become input in formulating a policy for providing affordable vertical housing in the Semarang that is well-suited to the socio-economic characteristics of its inhabitants.


Introduction
Semarang, a city in Indonesia, continues to grow and urbanize rapidly, developments that are influenced by population growth.In addition, the city's economy is also experiencing rapid growth.According to data from the Semarang City Office of Statistics, in 2021, the economic growth rate for Semarang reached 5.16%, which was higher than the economic growth rate in Jakarta for the same year 2 [1].Population and economic growth affect the city's physical development, especially related to fulfilling the population's occupancy needs [2].
An increasing population and a growing economy typically lead to an increased need for proper housing, a basic human need [3].Population growth, increased housing requirements, and a lack of available land in urban areas motivate developers to construct vertical housing [4].However, fulfilling this need is difficult, especially in urban areas like Semarang.The amount of available land is limited and continues to decrease, causing land prices to increase [5].Along with Semarang's increasing population and growing economy, the need for housing has also increased.One effort to overcome the problem of housing availability in the context of limited land and high land prices in Semarang involves building vertical housing.Traditional residential development usually occupies significant urban spaces but can be controlled by pushing for increased vertical housing development.This concept of vertical housing can help urban developments in developing open spaces into green spaces.However, the realization sometimes results in reducing social aspects within the community [6].
Vertical housing standards in Indonesia have evolved through three phases since 1983.First, in the 1980s and early 1990s, communal facilities were placed at both ends of a double-loaded corridor system.The second type was piloted from the mid-1990s to the mid-2000s; during this period, the shared facilities were diminished in size and replaced by individual facilities within each unit.Finally, since the mid-2000s the double-loaded corridor system has been replaced by single-loaded corridors, to maximize the natural lighting and ventilation for every unit as well as interaction among residents [7].
Vertical housing in Semarang City began to emerge in 1992 and continues to grow today.Currently, there are 10 blocks of low-cost flats with 2,650 residential units and 14 apartment buildings with 4,971 residential units.In providing vertical housing, it is first necessary to know the characteristics of the people who need it.According to Bourne, cited in Yuniarti [8], individuals' decisions regarding their residence are influenced by social and economic conditions.Differences in socio-economic characteristics affect their needs and housing choices.When planners fail to consider potential residents' socio-economic conditions, mistakes can occur in providing vertical housing, and housing becomes unavailable and unaffordable for the community.
Currently, several problems exist concerning vertical housing in Semarang, such as apartments with low occupancy, a decrease in demand for apartments of up to 100%, indications of a shortage of units, and the misuse of flats [9,11].Moreover, several factors indicate that the available vertical housing does not match residents' economic situation.The current vertical housing providers have not successfully understood the characteristics of the community in Semarang.For this reason, it is necessary to investigate the socio-economic characteristics of the current occupants of vertical housing so that dwellings constructed in the future can meet their needs.Without this knowledge, errors may occur in the types of housing provided, so the accommodation is not suitable for the socio-economic characteristics of its inhabitants.Therefore, this research aims to determine the relevance of vertical housing to residents' socio-economic characteristics particularly in proximity of public facility aspects.In other words, to answer the question of "How is vertical housing relevant to the socio-economic characteristics of its inhabitants in the City of Semarang: particularly in the proximity of public facility aspects"

Research Methods
To achieve the research objective, this research used quantitative descriptive research method.Importance-performance analysis use to determine the relevance of vertical housing to residents' socioeconomic characteristics and geospasial tools use to analyze descriptively the proximity of public facilities.Questioners and direct observation use as the data collection technique.The questionnaires were distributed to vertical housing residents in the City of Semarang using random cluster sampling.The research population was defined as 7,261 vertical housing units, and a sample size calculation was carried out using the Slovin formula: The obtained sample size of 98.7 was rounded up to 99 vertical housing residents in Semarang with the following distribution (Table 1).Respondents were selected by first dividing the population into two groups: the apartment group and the low-cost flat group (Figure 1).Then, two flats and four apartment buildings were chosen as clusters based on a comparison of the number of residential units.From each building, a random and proportional selection of respondents was carried out using the number of units as the assumed population of vertical occupants.Thus, the respondents comprised randomly selected vertical housing residents, and each respondent represented one unit.
Quantitative descriptive analysis techniques were used to identify the socio-economic characteristics of the vertical housing occupants in Semarang [12].The variables included occupants' age, educational level, number of family members, type of work, income, and household expenses.Importance performance analysis was used to analyze the relevance of vertical housing in Semarang to the socio-economic characteristics of its inhabitants.The variables included residential architectural design or style, residential unit area, number of bedrooms, build quality, distance from residence to workplace proximity to public facilities, easy access to public transportation (Figure 5), affordable housing prices, payment schemes, environmental safety, environmental hygiene, good social interaction, availability of green open space (Figure 6), availability of children's play area, availability of communal space, completeness of settlement infrastructure.The data were obtained from questionnaires using a Likert scale, with 1 corresponding to very unimportant or dissatisfied and 5 to very important or very satisfied.
A validity test was carried out to determine whether the measuring instrument, in this case, the results obtained from the questionnaire, were valid or invalid.The data can be declared valid if r counts > r table.Conversely, if r counts < r table, the data can be declared invalid.This study conducted questionnaire validity tests on the 99 respondents using SPSS.Furthermore, reliability tests were conducted to determine the consistency of the questionnaire used in this study.The test was performed using SPSS.The questionnaire can be declared reliable or consistent if the value of Cronbach's Alpha is greater than 0.70 [13].The questionnaire can be declared inconsistent if Cronbach's Alpha is less than 0.70.In the importance-performance analysis, the level of importance and suitability of residential attributes according to its occupants was analyzed using the following formula: Then an analysis of relevance or suitability was carried out using the following formula: If the suitability level is above 100%, it can be considered well-suited or relevant.However, if the suitability level is below 100%, it is considered not relevant.The level of non-conformance is divided into three levels.The first level, with a concordance level of 0-32%, is considered very irrelevant, a concordance level of 33-65% is considered irrelevant, and a concordance level of 66-99% is considered less relevant.Lastly, the level of importance and level of performance as gathered from the respondents were mapped into the following four quadrants: The four quadrants indicate conditions of importance and variable performance (Figure 2), which can then be used as input for policy-making with the following explanation: a. Quadrant I (Concentrate Here) Contains variables that are considered important but have unsatisfactory performance and need to be improved.
b. Quadrant II (Keep Up the Good Work) Contains variables that are considered important and have satisfactory performance and need to be maintained or improved.
c. Quadrant III (Low Priority) Contains variables that are considered less important with unsatisfactory performance, so they do not need to be prioritized to improve performance.
d. Quadrant IV (Possible Overkill) Contains variables that are considered less important but have satisfactory performance.Resources can be allocated to more important variables, such as those in Quadrant I.

Socio-Economic Characteristics of Vertical Residential Occupants in the City of Semarang
Identifying the socio-economic characteristics of vertical housing occupants provides information on the profile of these Semarang residents.Socio-economic characteristics connote a family's position in a community concerning prevailing standards of cultural ownership, effective income, material possessions, respectability, and social participation [14].These characteristics affect the type of occupancy chosen and occupants' performance and importance ratings of their dwelling.The study identified several socio-economic characteristics: age, education level, number of family members, type of work, income, and household housing expenses.
An independent t-test was conducted to determine whether significant differences existed in the socio-economic characteristics of respondents living in apartments and flats in Semarang.The study found significant differences in the socio-economic characteristics of apartment and flat dwellers in Semarang.As seen in Table 2, most apartment residents are younger than the residents of the flats.Most apartment occupants live alone, in contrast to flats, the majority of which are occupied by families of four.Occupants' level of education also differs, with most apartment residents having a college education and most flat residents having completed high school or the equivalent.The majority of apartment residents work as private employees or are students (denoted as "other" in the table), while the majority of flat residents work as laborers.In connection with different types of work, the income generated also varies.Apartment residents generally have a higher income, in the range of Rp. 7,500,000-Rp.10,000,000, while the income of most flat residents is ≤ Rp. 3,000,000.
Differences in socio-economic characteristics between residents affect their desires and needs in choosing their housing [15].These varying characteristics of apartment dwellers and flat residents affect their lifestyles, needs, and ability to live in different types of vertical housing.As a result, differences may emerge in the level of performance, importance, and relevance of occupancy in these two vertical housing types.

Relevance and Occupancy Typology in Semarang City
The study used importance-performance analysis (IPA) to determine occupancy relevance.The IPA technique is used to map the relationship between the ratings of importance and performance for each attribute and the gap between the rating of importance and the rating of performance of these attributes [16,17].A total of 16 attributes were investigated by distributing questionnaires to 53 respondents who lived in apartments and 46 residents of flats.Different occupancy conditions led to differences in residents' assessments of the importance and performance of the attributes in each type of occupancy.As a result, significant differences emerged in the rating of performance and suitability between types of vertical housing but not in the rating of importance.Table 3 shows that apartment residents consider environmental cleanliness the most important attribute, with a score of 4.68.In contrast, the attribute they consider the least important is the availability of children's playgrounds, with a score of 2.94.Regarding satisfaction, the attribute with the most satisfactory performance, according to apartment residents, is proximity to public facilities.No apartment attributes are considered unsatisfactory because all attributes have scores above three.The attribute with the lowest performance score is the availability of a children's playground, with a score of 3.06.Similar to apartment residents, the attribute of flats that residents consider the most important is environmental cleanliness, with a score of 4.59.However, flat dwellers differ from apartment dwellers in the attribute they consider the least important, namely the availability of green open space, with a score of 2.74.Compared to apartments, the performance scores for the attributes of flats tend to be lower.The attribute of flats that residents consider to have the most satisfactory performance is the payment scheme, with a score of 3.96.Meanwhile, the attribute whose performance residents consider least satisfactory is the availability of children's playgrounds, with a score of 2.33.
As seen by comparing Table 3 and Table 4, the apartment residents' importance ratings are almost the same as those of the residents of the flats.However, the groups of residents gave priority to different attributes.The rating of importance reflects occupants' preferences for the attributes of their dwelling.These results indicate that socio-economic characteristics have less influence on preference for residential attributes.This contrasts with Mulliner and Algrnas [18], who argue that socio-economic characteristics influence individual preferences for residential attributes.The similarity in the rating of importance found in this study may be caused by the Semarang respondents' similar cultural backgrounds.Indeed, culture is another aspect that influences housing preferences [18].In contrast, a significant difference was observed in apartment and flat residents' performance ratings.The results of the performance ratings align with the findings of Yetunde and Bayo [19], who argue that performance ratings vary based on socio-economic characteristics.In particular, individuals with better economic backgrounds can meet their housing needs and are more satisfied.
Next, the study measured the gap of importance and performance rating perceive by the vertical occupant.The smaller the gap between the rating of importance and the rating of performance, the higher the level of relevance [16].Attributes with a relevance level above 100% can be considered relevant [16].Table 5 shows the relevance level of the apartment and flat occupancy attributes.The results demonstrate a significant difference between the relevance level of apartments and flats in Semarang City.Ease of access to public transportation, distance from residence to the workplace, and proximity to public facilities are considered relevant for apartment residents.In accordance with the apartment typology, residents-dominated by private employees and students-tend to be active in places related to their work.The average distance to locations of activity is 7 km.The number of bedrooms and the area of the unit are considered relevant because most apartment residents live alone and are in their 30s, so one bedroom is enough.In addition, even though the average apartment complex does not have a communal space or a children's play area, apartment residents tend not to mind this.Apartment dwellers mostly fit into the early working age group and spend more time outside the home than around the house.Thus, communal space is rarely used, and social interaction seldom occurs.Similarly, a study in the City of Bandung found that socio-cultural aspects, such as the quality of social interaction, do not affect importance in vertical housing [20].
In contrast to the relevance level of apartments, only four attributes are relevant for flat dwellers.These four attributes are the availability of communal space, design, payment schemes, and good social interaction.All flats in Semarang City have a communal space in the form of a hall on the ground floor of each building.In addition, several blocks of flats have an empty space on each floor that functions as a gathering place.Regarding the attributes of good social interaction, the respondents' opinions of the flats fell into two groups regarding satisfaction with social interaction.The younger group considered social interaction less important because they tend to spend time outside the home for work or school.
As many as 12 attributes of flats are considered irrelevant, with the three most irrelevant attributes being the area of the unit, the availability of children's play areas, and environmental cleanliness.Based on study observations, almost no flats have a special area designated as a children's play area, even though the average flat is occupied by a family of four with two children.They tend to play in the hallway area and in front of the building.The size of the residential unit and the number of bedrooms is irrelevant, related to the number of families with an average of four people.According to SNI 03-1733-2004 on the procedures for planning residential environments in urban areas, the standard minimum requirement for a residential area is 9 m 2 /person [21].Therefore, when four or more people occupy a flat with an area of 21 m 2 , 24 m 2 , or 27 m 2 , their standard needs remain unmet.In addition, for families with older or many children, residential units with one or two bedrooms are not ideal.While the occupancy does not violate the rules, it does not meet occupants' standards and needs.The results indicate that the attributes of apartment occupancy are more relevant than those of flats.This is caused by differences in building typology and the inhabitants' socio-economic characteristics.In apartments, nine attributes have a suitability level above 100% and are thus considered relevant, whereas only four attributes are relevant in flats.Therefore, vertical housing-including apartments and flats-in the city of Semarang is largely irrelevant to the socio-economic characteristics of its inhabitants.
Furthermore, the levels of importance and performance according to the respondents were mapped onto the four quadrants.This mapping was done to provide input to vertical shelter providers regarding what steps to take in the future.As noted above, the four quadrants are quadrant I, concentrate here; quadrant II, keep up the good work; quadrant III, low priority; and quadrant IV, possible overkill [22].Figure 3 shows that the 16 apartment attributes are spread over the four quadrants as follows: a. Quadrant I (Concentrate Here) Three attributes belong in the concentrate here quadrant: the affordability of housing prices, payment schemes, and completeness of settlement infrastructure.Apartment residents considered these three attributes important yet unsatisfactory.They see the prices as unfordable, the payment schemes as insufficient, and the infrastructure as incomplete.In this context, settlement infrastructure includes road networks, clean water, drainage, electricity, sanitation, and solid waste management [23].Apartment providers must pay attention to and prioritize improving the performance of these attributes.b.Quadrant II (Keep Up the Good Work) The following six attributes of apartment occupancy fit in this quadrant: • Residential architectural design or style Only two attributes appear in this quadrant, namely the area of the residential unit and ease of access to public transportation.While their performance is satisfactory, these two attributes are considered less important by apartment dwellers.Thus, the apartment manager or provider does not need to focus their resources on this attribute.
Next, Figure 4 illustrates that the 16 attributes of flats are also scattered over the four IPA quadrants, detailed as follows: a. Quadrant I (Concentrate Here) This quadrant includes three attributes: the distance from the residence to the workplace, environmental cleanliness, and proximity to public facilities.While the occupants of the blocks of flats consider these three attributes important, they also expressed that they do not currently meet their needs.Therefore, the providers or managers of the flats should pay attention to and prioritize the improved performance of these attributes.b.Quadrant II (Keep Up the Good Work) The occupants of flats identified the following five essential attributes as satisfactory: • Build quality • Affordable housing prices • Payment scheme • Environmental safety • Completeness of settlement infrastructure The rental flat providers should aim to maintain and improve the performance of these attributes.c.Quadrant III (Low Priority) The following five attributes of flats are considered unsatisfactory but less important by the occupants: • Residential unit area Although the flat residents view the performance of the above five attributes as unsatisfactory, they do not see this as a significant problem.The most critical issue is access to affordable housing due to their limited economic means.They need to feel secure about their limited stay in the flats [24].Therefore, rental flat providers should continue to maintain the performance of these attributes but not prioritize improving them.d.Quadrant IV (Possible Overkill) Three attributes of low-cost flats fall into this quadrant: design, good social interaction, and availability of communal space.Flat residents consider these three attributes to be satisfactory but unimportant.The appropriate response for the flat provider would be to allocate the resources to the attributes in quadrant I.
As seen above, apartment and flat housing providers should prioritize different actions.Apartment occupants tend to be dissatisfied with economic factors, while flat occupants tend to be dissatisfied with accessibility factors, such as the distance from their residence to the workplace and proximity to public facilities.As a result, the private sector and the government should focus on different aspects of managing and providing vertical housing in the City of Semarang.As an apartment provider, the private sector can focus on reviewing the economic capacity of the target housing provider.Meanwhile, as a provider of low-cost flats, the government can focus on reviewing the location of low-cost housing developments and/or adding the required public facilities.

The Proximity of Public Facility Aspects: A Descriptive Analysis
In this research we have three aspects of public facility.First, public transportation facility (see Figure 5).Second, public space facilities (see Figure 6).Last, the public facility of education and medical facilities (see Figure 7).Based on the previous analysis (see Table 5), the most relevance aspect for the apartment resident is the ease of access to public transportation.As seen in Figure 5 that the location of apartments in Semarang City is adjacent to public transportation facility, such us bus station.In other hand, for flat residents most relevance attributes are the availability of communal space in their area.For flat resident environmental hygiene is the most importance attribute, but the performance that they get are not adequate.So, the relevance level of environmental hygiene is the last relevance level for flat residents.As seen as Figure 6 the distribution of open space facilities is spread quite evenly, especially in areas adjacent to apartments.While in the area adjacent to the flat there is only graveyard.However, based on the results of the analysis that has been carried out, the relevance value of the availability of green open space for residents in flat is higher than residents in apartments.This can happen because the importance value for the availability of public green open space for people who live in flat is lower than people who live in apartments.On the other hand, for the availability of Education and medical facilities (see Figure 7).The availability of education is spread very evenly both in areas adjacent to apartments and adjacent to flats.However, for health facilities in the flat area there are only a few points.This is quite clearly illustrated in the analysis on the Table 5 that the relevance of the proximity of these public facilities to people living in flats is quite low.This happens because the proximity from the flat to the education and medical facilities is quite far.

Conclusion
The study finds some differences in the importance ratings of apartment and flat occupants.Proximity to public facilities and ease of access to public transportation are more important for residents living in apartments compared to residents living in flats.On the other hand, the study found significant differences in how apartment and low-cost housing residents rated the performance of their housing.This indicates that performance ratings differ based on socio-economic characteristics.Individuals in a stronger economic situation can better meet their housing needs and are thus more satisfied.
Based on the relevance analysis, it can be concluded that the relevance between residents in apartments and residents in flats has some differences.This could happen because of differences in the location of apartment areas that tend to be in the center of activity area, while flat areas tend to be in areas farther from the center of activity.In addition, this is also due to the difference in financial capabilities between residents in apartments and residents in flats.So, residents who live in flats tend not to be able to accommodate their needs.
To increase the relevance of vertical housing, the private sector and the government must change their focus in managing and providing vertical housing in City of Semarang.Private parties, such as managers and apartment providers, should focus on improving the performance of economic factors.As the manager and provider of low-cost flats, the city government can focus on improving the performance of the accessibility factor.This must be done so that both the existing vertical housing and that which Semarang plans to build can be more relevant to the socio-economic characteristics of its inhabitants.

Acknowledgement
The research has been fully funded by DRPM, DIRJEN RISBANG, KEMENRISTEKDIKTI RI, Indonesia, with the support from the Department of Urban and Regional Planning, Faculty of Engineering, Diponegoro University, Indonesia.The authors are very grateful for the continuous support from these institutions, which have made this research well delivered.

Figure 7 .
Figure 7. Availability of Education and Medical Facility (Analysis, 2023)

Table 2 .
Socio-Economic Characteristics of Vertical Residential Residents in Semarang City

Table 3 .
Importance and Performance Ratings of Residents of Apartments in Semarang City

Table 4 .
Importance and Performance Ratings of Residents of Flats in Semarang City Source: Analysis, 2023

Table 5 .
Vertical Residential Relevance Level in Semarang City