Gentrification and urban gentrification denote the socio-cultural changes in an area resulting from wealthier people buying housing property in a less prosperous community. Consequent to gentrification, the average income increases and average family size decreases in the community, which may result in the informal economic eviction of the lower-income residents, because of increased rents, house prices, and property taxes. This type of population change reduces industrial land use when it is redeveloped for commerce and housing. In addition, new businesses, catering to a more affluent base of consumers, tend to move into formerly blighted areas, further increasing the appeal to more affluent migrants and decreasing the accessibility to less wealthy natives.
Urban gentrification occasionally changes the culturally heterogeneous character of a community to a more economically homogeneous community that some describe as having a suburban character. This process is sometimes made feasible by government-sponsored private real estate investment repairing the local infrastructure, via deferred taxes, mortgages for poor and for first-time house buyers, and financial incentives for the owners of decayed rental housing. Once in place, these economic development actions tend to reduce local property crime, increase property values and prices and increase tax revenues.
Political action, to either promote or oppose the gentrification, is often the community’s response against unintended economic eviction  caused by rising rents that make continued residence in their dwellings unfeasible. The rise in property values causes property taxes based on property values to increase; resident owners unable to pay the taxes are forced to sell their dwellings and move to a cheaper community.
Gentrification has happened since ancient times; in Britain large villas were replacing small shops by the third century. The word gentrification is of much later origin. It derives from gentry, which is derived from the Old French word genterise denoting “of gentle birth” (14th c.) and “people of gentle birth” (16th c.); which in England denoted the highest social class below the nobility. In 1964 the British sociologist Ruth Glass coined the term “gentrification” to denote the influx of middle-class people to cities and neighborhoods, displacing the lower-class worker residents; the example was London, and its working-class districts such as Islington:
One by one, many of the working class neighborhoods of London have been invaded by the middle-classes—upper and lower. Shabby, modest mews and cottages—two rooms up and two down—have been taken over, when their leases have expired, and have become elegant, expensive residences ... Once this process of 'gentrification' starts in a district it goes on rapidly, until all or most of the original working-class occupiers are displaced and the whole social character of the district is changed.
In the US, the Centers for Disease Control and Prevention report Health Effects of Gentrification defines the real estate concept of gentrification  as “the transformation of neighborhoods from low value to high value. This change has the potential to cause displacement of long-time residents and businesses . . . when long-time or original neighborhood residents move from a gentrified area because of higher rents, mortgages, and property taxes. Gentrification is a housing, economic, and health issue that affects a community’s history and culture and reduces social capital. It often shifts a neighborhood’s characteristics (e.g. racial–ethnic composition and household income), by adding new stores and resources in previously run-down neighborhoods.” 
In the Brookings Institution report Dealing with Neighborhood Change: A Primer on Gentrification and Policy Choices (2001), Maureen Kennedy and Paul Leonard say that "the term 'gentrification' is both imprecise and quite politically charged", suggesting its redefinition as "the process by which higher income households displace lower income residents of a neighborhood, changing the essential character and flavor of that neighborhood", so distinguishing it from the different socio-economic process of “neighborhood (or urban) revitalization”, although the terms are sometimes used interchangeably.
Two discrete, sociologic theories explain and justify gentrification as an economic process (production-side theory) and as a social process (consumption-side theory) that occurs when the suburban gentry tire of the automobile-dependent urban sprawl style of life; thus, professionals, empty nest aged parents, and recent university graduates perceive the attractiveness of the city center—earlier abandoned during white flight—especially if the poor community possesses a transport hub and its architecture sustains the pedestrian traffic that allows the proper human relations impeded by (sub)urban sprawl.
The production-side theory of urban gentrification derives from the work of Professor Neil Smith, explaining gentrification as an economic process consequent to the fluctuating relationships among capital investments and the production of urban space. Low rents in the city’s periphery, during the two decades after the Second World War (1939–45), provoked continuous diversions of city housing capital for the development of suburbs and rural areas. That spending of city money on suburbs then devalued inner-city capital property, provoked the economic abandonment of the city in favor of peripheral rural property, consequently, the low price of inner-city land, relative to the high price of rural land. From this derives the Rent-gap Theory describing the disparity between "the actual capitalized ground rent (land price) of a plot of land given its present use, and the potential ground rent that might be gleaned under a 'higher and better' use".
The rent gap is fundamental to explaining gentrification as an economic process. When the gap is sufficiently wide, real estate developers, landlords, and other people with vested interests in the development of land perceive the potential profit to be derived from re-investing in inner-city properties and redeveloping them for new tenants. Such redevelopment effectively closes the rent gap, leading to higher rents, mortgages, and lease rates affordable by the new tenants, but not by the original working-poor tenants.
Furthermore, the de-industrialization of a city reduces the number of blue-collar jobs available to the urban working class—lost investment capital needed to physically maintain the houses and buildings of the city. De-industrialization is often integral to the growth of a divided white collar employment tertiary sector of industry, some of whom take the professional and management jobs that follow the spatial centralization of capital—i.e. corporations requiring that employees live near their workplace to reduce corporate decision-making time.
The consumption-side theory of urban gentrification posits that the “socio-cultural characteristics and motives” of the gentrifiers are most important to understanding the gentrification of the post-industrial city —characterised by an "employment profile focused on advanced services ... [a] profile that is materialized in a downtown skyline of office towers, arts and leisure sites, and political institutions. Its middle-class ambiance may be reflected in a distinctive politics, charged with a responsible social ethos ... the demand for more amenities, for greater beauty and a better quality of life in the arrangement of our cities".
As such, David Ley posits a rehabilitated post-industrial city influenced by a "new middle class" containing a cultural sub-class denominated as a creative class of artists, teachers, and cultural administrators. They are the first-stage gentrifiers economically preparing the inner city for gentrification—by introducing to the city the rich bourgeois politics characterised by diminished public funding for housing affordable to middle- and low-income residents, draconian residency laws against the homeless and the poor displaced when "artists move into otherwise undesirable buildings, [and] usually make significant improvements to their spaces, and their surrounding areas. Everyone benefits from these tenuous and uneasy ... arrangements. Then, landlords becoming aware that they are sitting on gold mines, rush to cash in".
To wit, sociologist Sharon Zukin reports the economic realities of the “artist loft” real estate business in Manhattan, when the owners of the building where she resided converted it to a "co-op" administration in 1979, and she "bade good-bye to the manufacturers, an artist, and several residents who could not afford the market prices at which our lofts were sold". In the event, rich lawyers and accountants, retail business people and investment bankers replaced the suburban “starving artist” bohemian “first-stage gentrifiers”  who initiated the gentrification of Hell's Kitchen, in mid-town New York City, Harlem, Washington Heights, Astoria, and areas of Brooklyn.
Professor Smith and Marxist sociologists explain gentrification as a structural economic process; Ley explains gentrification as a natural outgrowth of increased professional employment in the central business district (CBD), and the creative sub-class’s predilection for city living. "Liberal Ideology and the Post-Industrial City" (1980) describes and deconstructs the TEAM committee’s effort to rendering Vancouver, BC, Canada, a "livable city". The investigators Rose, Beauregard, Mullins, Moore et al., who base themselves upon Ley’s ideas, posit that "gentrifiers and their social and cultural characteristics [are] of crucial importance for an understanding of gentrification"—theoretical work Chris Hamnet criticized as insufficiently comprehensive, for not incorporating the "supply of dwellings and the role of developers [and] speculators in the process".
Gentrification is integral to the new economy of centralized, high-level services work—the "new urban economic core of banking and service activities that come to replace the older, typically manufacturing-oriented, core"  that displaces middle-class retail businesses so they might be "replaced by upmarket boutiques and restaurants catering to new high-income urban élites". In the context of globalization, the city’s importance is determined by its ability to function as a discrete socio-economic entity, given the lesser import of national borders, resulting in de-industrialized global cities and economic restructuring.
To wit, the American urban theorist John Friedman’s seven-part theory posits a bifurcated service industry in world cities, composed of "a high percentage of professionals specialized in control functions and ... a vast army of low-skilled workers engaged in ... personal services ... [that] cater to the privileged classes, for those whose sake the world city primarily exists". The final three hypotheses detail (i) the increased immigration of low-skill labourers needed to support the privileged classes, (ii) the class and caste conflict consequent to the city’s inability to support the poor people who are the service class, and (iii) the world city as a function of social class struggle—matters expanded by Saskia Sassen et al. The world city’s inherent socio-economic inequality illustrates the causes of gentrification, reported in "Where Did They Go? The Decline of Middle-Income Neighborhoods in Metropolitan America" (2006) demonstrating geographical segregation by income in US cities, wherein middle-income (middle class) neighborhoods decline, while poor neighborhoods and rich neighborhoods remain stable.
In US cities, the suburban gentrifiers often resemble the populace who earlier abandoned the city in the phenomenon of white flight. From this perspective gentrification is merely the sociological reverse of white flight from a culturally barren suburbia to the culturally fertile city. The consumption-side theory of gentrification requires the existence of a service sector economic class of university-educated adults (aged 25–45) with disposable income who wish to live near their jobs in the city. This economic class arose when most Western economies transitioned from manufacturing to post-industrial service economies.
Gentrification-increased property values are a positive economic development for cities when tax revenues increase consequent to increased property values, however existing residents experience the change as increased property taxes. The increased taxes force many original property owners to either pay and stay (via higher rents for their tenants) or to sell and leave the gentrifying community. In gentrying communities without strong rent-control laws the working poor are informally evicted when they cannot afford the increased rents. As a result, such economically limited people usually oppose gentrification, because it destroys the community that first attracted the gentrifiers to the city—despite the claim of that gentrification improves the city. Recent research has demonstrated a correlation between gentrification and decreased voter participation in US and Canadian cities.
In Finland, the phenomenon, called syrjäytyneiden akanvirta in Finnish, meaning "migration of the disadvantaged", has begun at wider range in the beginning of 2000s, when living costs in larger cities have grown. The welfare support isn't large enough to live in bigger cities when housing costs rise because housing situation is hard in the cities. Marginalized people have also many problems in living, so there is a constant fear of eviction from municipality-owned public housing. People who are poor and suffer from many problems of controlling their lives, move out to cheap private-owned housing very far away, where living is cheap. There are a number of businessmen, who buy old school buildings and renovate them to housing. The businessmen then offer these apartments as "a place of last resort" for "difficult" cases, that municipalities are reluctant to take into public housing apartments. Even the most marginalized people are welcomed to this kind of housing. Municipalities that have acknowledged the migration include Ilomantsi, Luhanka, Puolanka, and Rääkkylä.
The suburban middle-class typically do not initiate gentrification of city neighborhoods, the process typically begins via “first-stage gentrifiers”, economically- and socially-marginal “trend setters”. Sociologically, these people are young and have low incomes while possessing the cultural capital (education and a job), characteristic of the suburban bourgeois. They often reside in communal (room-mate) households, and are more tolerant of the perceived evils of the city—crime, poor schools, insufficient public services, few shops, and the presence of non-white people—that dissuade suburban middle-class families.
The gentrification of a city community proceeds when the number of trend-setters multiplies to the degree that business re-investment reappears in the form of the social amenities the bourgeoisie values—bars, restaurants, and commercial art galleries. The renewed business attracts other people of like socio-economic outlook, and investment capital follows, thus increasing local property values. Once the pioneer business entrepreneurs haven taken the financial risk out of the gentrified city community the way is opened for more risk-averse investors and residents to enter the “new” city neighborhood. Upon full gentrification, the “first-stage gentrifiers” are often (informally) economically evicted via higher rents, mortgages and property taxes.
Urban gentrification does not always require the intermediate steps outlined. Central planning combined with investment can facilitate a more direct transition from under-development to gentrification as in the London Docklands, and other CBD-adjacent urban renewal projects. The comprehensive public-housing redevelopment of the Cabrini-Green ghetto in Chicago, Illinois in the US provides a pertinent example: government and large private developers invested in poor communities with capital sufficient to forgo the intermediate stages of gentrification, successfully stabilising an urban neighborhood so that the middle class desired to live there. Some additional examples are Roxbury, Massachusetts, Fell's Point, Baltimore, the Near South Side, Chicago, and Harlem, New York City, and, in Europe, Prenzlauer Berg, Berlin, Altona, Hamburg, Ferencváros, Budapest, and Islington, London.
In the course of gentrification, an artist colony in the city is transformed from a poor to a rich neighborhood when artists and sub-culture aficionados (e.g. hipsters, hippies, et al.) live in poor neighborhoods of devalued real estate, because of the low rents, central locale in the city proper, and "gritty" cultural “sense of authenticity”, of being true to life. As the bohemian character of the community grows, it appeals "not only to committed participants, but also to sporadic consumers"  who eventually economically push out the earlier arrival sub-culture aficionados. Hence gentrification’s economic eviction of hippies from the East Village, Manhattan, New York City, in the 1960s:
By the early 1960s, the Beats' enclave of Greenwich Village had been ... commercialized by middle-class onlookers ... Between 1964 and 1968, dozens of specialty shops that catered to the hippies had opened along St. Mark's Place ... In addition to students and hippies, the neighborhood's countercultural atmosphere attracted copywriters, editorial workers, fashion designers, and commercial artists ... Although the youthful movement criticized middle-class values and lifestyles, its members, nonetheless, were of largely middle-class origin living in one of the poorest working-class districts in the city.
Throughout the 1960s and 1970s, Manhattan lofts in SoHo were converted en masse into housing for artists and hippies, and then their sub-culture followers. As the price of living—and consequent social status—in those neighborhoods rose, the artists moved to Park Slope, Brooklyn and Hoboken, New Jersey, and Williamsburg, Brooklyn. The areas from where gentrification is evicting hipsters run the BMT Canarsie Line (L) and IND Crosstown Line (G) of the New York City Subway system, for being near Williamsburg. Adjacent hipster enclaves include neighboring Bushwick and Flatbush although these neighborhoods are also seeing higher rents. Like gentrification occurred throughout the 1990s and 2000s in the East Village and the Lower East Side of New York City, economically pushing out theatres and performance-art spaces such as Collective:Unconscious, Surf Reality, House of Candles, Piano's (Theater), and The Present Company.
Manuel Castells's seminal work about gay men as "gentrifiers" in San Francisco, California, shows that "many gays were single men, did not have to raise a family, were young, and connected to a relatively prosperous service economy" is a pattern replicated in other North American cities. An illustration of this sociologic phenomenon is the film Quinceañera (2006), directed by Richard Glatzer and Wash Westmoreland, containing a thematic sub-plot about the gentrification of the protagonists’ inner-city neighborhood, Echo Park in Los Angeles, CA.
The documentary Flag Wars (2003), directed by Linda Goode Bryant, shows the social, class, and gender tensions in the Silk Stocking neighborhood in Columbus, Ohio, between an urban African-American community and the mostly white gays and lesbians moving in to the neighborhood, whom the original residents accused of gentrification and racism. In turn, the new residents accused the community of homophobia. In 2006, in Washington, D.C., a religious congregation in the black Shaw neighborhood opposed the granting of a liquor license to a gay bar that was to open across the street from the church. The bar was successfully opened and has since been replaced by another gay bar at the same location.
Gay people are not always the gentrifiers: real estate valuation trends can push out poor gay people, as in the Polk District in San Francisco; radical gay activists saw the value of a poor neighborhood as refuge for the economically, sexually, and socially marginal.
To counter the gentrification of their mixed-populace communities, residents formally organized themselves to develop the necessary socio-political strategies required to retain local affordable housing; many such organizations arose in the 1960s, and used the pragmatic tactics advocated by the late Saul Alinsky (1909–72). In the late 1960s, the Young Lords Chicago street gang — who were politically active in the then-Puerto Rican neighborhood of Lincoln Park — practiced the direct-action techniques of sit-in protests and occupying vacant community lands. In Miami, Florida, the Liberty City community organization “Take Back the Land” seized empty lands and built the Umoja Village shantytown for the community’s homeless people in October 2006. Like-wise, other communities established community development corporations that include the residents in actively developing their neighborhoods.
When wealthy people move into low-income, working class neighborhoods, class conflict results — sometimes manifested as “direct action and sabotage”, ranging from vandalism of and arson against the properties of the gentrifiers. In the late 1990s, during the dot-com boom, the gentrification of the working class Mission District, San Francisco, California, provoked the community’s establishing of the “Mission Yuppie Eradication Project” political action group who (allegedly) destroyed property as part of their strategy against local gentrification; their destructive politics drew hostile responses from the San Francisco Police Department, local real estate interests, and from “work-within-the-system” affordable housing activists.
The gentrification of a mixed-income community raises housing affordability to the fore of the community’s politics. Cities, municipalities, and counties have countered gentrification with inclusionary zoning (inclusionary housing) ordinances requiring the apportionment of some new housing for the community’s original low- and moderate-income residents. Because inclusionary zoning is a new social concept, there are few reports qualifying its effective or ineffective limitation of gentrification. In Los Angeles, California, inclusionary zoning apparently accelerated gentrification, as older, unprofitable buildings were razed and replaced with mostly high-rent housing, and a small percentage of affordable housing; the net result was less affordable housing.
Besides the informal, economic eviction of the community’s poorer residents, another detrimental aspect of gentrification is its negative economic impact upon the community’s commerce. Often, a neighborhood in mid-gentrification has marketable artist colony cachet that renders it popular, because of its nightlife, light industry, and arts-and-crafts businesses. In the event, the (ex-suburban) new-resident gentry complain to local government about the artist-colony “noise”, pressuring the authorities to impose financially-onerous noise-limitation requirements that eventually (and informally) evict said urban pioneer businesses. In New Zealand, this practice is called reverse sensitivity, a novel approach whereby the local gentry use land-use zones to identify feasible “reverse sensitivity” matters, i.e. “noisy neighbors” who then must meet zoning requirements mitigating their noise, or leave.
Zoning ordinances and other urban planning tools can also be used to recognize and support local business and industries. This can include requiring developers to continue with a current commercial tenant or offering development incentives for keeping existing businesses, as well as creating and maintaining industrial zones. Designing zoning to allow new housing near to a commercial corridor but not on top of it increases foot traffic to local businesses without redeveloping them. Businesses can become more stable by securing long-term commercial leases.
Because land speculation tends to raise property values, removing real estate (houses, buildings, land) from the open market stabilises property values, and thereby prevents the economic eviction of the community’s poorer residents. The most common, formal legal mechanism for such stability is the community land trust; moreover, many inclusionary zoning ordinances formally place the "inclusionary" housing units in a land trust.
In jurisdictions where local or national government has these powers, there may be rent control regulations. Rent control restricts the rent that can be charged, so that incumbent tenants are not forced out by rising rents. If applicable to private landlords it is a disincentive to speculating with property values and reduces the incidence of dwellings left empty (and limiting availability of housing for new residents). If the law does not restrict the rent charged for dwellings that come onto the rental market (formerly owner-occupied or new build), rents in an area can still increase. The cities of southwestern Santa Monica and eastern West Hollywood in California, USA gentrified despite - or perhaps, because of - rent control.
Occasionally, a housing black market develops, wherein landlords withdraw houses and apartments from the market, making them available only upon payment of additional key money, fees, or bribes—thus undermining the rent control law. Many such laws allow "vacancy decontrol", releasing a dwelling from rent control upon the tenant’s leaving—resulting in steady losses of rent-controlled housing, ultimately rendering rent control laws ineffective in communities with a high rate of resident turnover. In other cases social housing owned by local authorities may be sold to tenants and then sold on. Vacancy decontrol encourages landlords to find ways of shortening their residents' tenure, most aggressively through landlord harassment. To strengthen the rent control laws of New York City, USA, housing advocates active in rent control in New York are attempting to repeal the vacancy decontrol clauses of rent control laws. Massachusetts, USA abolished rent control in 1994; afterwards, rents rose, accelerating the pace of Boston’s gentrification; however, the laws protected few apartments, and confounding factors, such as a strong economy, had already been raising housing and rental prices.
In Loft Living (1989), sociologist Sharon Zukin reports an apparently contradictory "Artistic Mode of Production", wherein patrician capitalists seek to increase the property values (i.e. gentrify) city communities by economically recruiting and retaining artists to reside in, and commercially occupy, the industrial buildings (usually) converted into an “artist’s loft complex”. First renting to urban pioneer “poor artists” develops the marketable artist colony cachet that appeals to suburban gentry seeking to buy a city dwelling; the gentrification imparts a commercially “hip” ambience to the surrounding community; in the event, property values rise.
Worldwide, cities with blighted communities effected public policy using this economic development model in poor neighborhoods; in the UK, the governments of Newcastle-upon-Tyne and Liverpool, via their regional development agencies, and in partnerships with private real estate speculators, attempted to artificially stimulate gentrification as urban renewal. In the US, the Jackson City, Michigan, city council re-developed a closed nineteenth-century state prison building-complex with affordable housing in the jail-house proper, and artist-loft spaces in the other buildings of the complex.
Economically, US municipal governments use tax increment financing (TIF) to rehabilitate decayed city communities with real estate development partnerships, between the municipal governments and public-private partnerships and non-profit organizations, and so offer subsidized, discounted-interest-rate mortgages to artists who buy property and reside in neighborhoods being gentrified, e.g. the Paducah Artist Relocation Program of Paducah, Kentucky. Per the TIF economic development model, the infrastructure improvements, public subsidies to private business, and consequent high property values, should encourage additional private real estate investment to the once-blighted urban community. The government re-activates the economy of the poor community with a TIF program that rehabilitates the infrastructure of the neighborhoods being gentrified; resultantly, property values and property tax revenues would rise. Moreover, for a fixed number of years, all of the TIF program-generated increased tax-revenues are paid to the TIF program-administration agency; to be spent only for improving the gentrified TIF district, and usually paid to the private real estate developer (a TIF program partner) responsible for improvements.
Although frequently disputed, many areas throughout Lebanon especially Beirut have been or are currently being gentrified. These areas include: Downtown Beirut, Sodeco area, and the Madhaf area.
This inner city suburb was an immigrant suburb of Greek and Vietnamese immigrants and refugees. Galleries, cafes and bars now line the shopping strips. High home prices and rent increases are reversing the white flight that took place 50 years ago.
Trastevere is rione XIII of Rome, on the west bank of the River Tiber, south of Vatican City; the Trastevere name derives from the Latin expression trans Tiberim (“beyond the Tiber"). Thanks to its partial isolation "beyond the Tiber" and to its multi-cultural populace, the Trasteverini developed a discrete culture since the Roman era. In 1744, Pope Benedict XIV (1740–58), recast the rioni (districts), thus demarcating Trastevere’s modern borders.
Contemporary Trastevere retains its character with its narrow cobblestone streets lined with mediæval houses, attracting tourists, artists, expatriates, and celebrities. In the 1960s and the 1970s, the American composers Frederic Rzewski and Richard Teitelbaum, of the group Musica Elettronica Viva (1966), lived in Via della Luce; and film director Sergio Leone is from Viale Glorioso. The institutional residents include the John Cabot University, the Pratt Institute School of Architecture, the American Academy, the Thomas More College of Liberal Arts, and the University of Waterloo School of Architecture.
Gentrification is not a new phenomenon in Britain; in ancient Rome the shop-free forum was developed during the Roman Republican period, and in second- and third-century cities in Roman Britain there is evidence of small shops being replaced by large villas.
King’s College London academic Loretta Lees reported that much of inner-city London was undergoing “super-gentrification”, where “a new group of super-wealthy professionals, working in the City of London, is slowly imposing its mark on this Inner London housing market, in a way that differentiates it, and them, from traditional gentrifiers, and from the traditional urban upper classes ... Super-gentrification is quite different from the classical version of gentrification. It’s of a higher economic order; you need a much higher salary and bonuses to live in Barnsbury" (some two miles north of central London).
Barnsbury was built around 1820, as a middle-class suburb, but after the Second World War (1939–45), people moved to the suburbs. The upper and middle classes were fleeing from the working class residents of London; the modern railroad allowed it. At war’s end, the great housing demand rendered Barnsbury the place of cheap housing, where most people shared accommodation. In the late 1950s and early 1960s, people moving into the area had to finance house renovations with their money, because banks rarely financed loans for Barnsbury. Moreover, the rehabilitating spark was The 1959 Housing Purchase and Housing Act, investing £100 million to rehabilitating old properties and infrastructure. Resultantly, the principal population influx occurred between 1961 and 1975; the UK Census reports that "between the years of 1961 and 1981, owner-occupation increased from 7 to 19 per cent, furnished rentals declined from 14 to 7 per cent, and unfurnished rentals declined from 61 to 6 per cent"; another example of urban gentrification is the super-gentrification, in the 1990s, of the neighbouring working-class London Borough of Islington, where Prime minister Tony Blair moved upon his election in 1997.
The Park Slope, Brooklyn neighborhood, located between Sunset Park and Downtown Brooklyn, was built at the end of the nineteenth century, for the wealthy, who commuted to work over the (then-newly built) Brooklyn Bridge. In the first decades of the twentieth century, the wealthy moved farther from the city, and working class people began to move in to reside. When the Great Depression (1929) occurred, the Park Slope neighborhood became a residential community for the extremely poor; most landlords allowed their housing properties to progress from disrepair to decrepitude.
In the 1950s and the 1960s, the US middle and upper classes moved yet farther from New York City, because of the suburbanisation the federal government made feasible with new roadways and mortgage programs, restricted to white people (cf. white flight). In 1966, the “Park Slope Betterment Committee” formed, and began buying and advertising houses to people whom they thought would be interested. In the mid-1970s, the middle class began returning to Park Slope, via gentrification; by the mid-1980s, most of the housing had been rehabilitated beyond the means of the previous residents, and by the mid-1990s the adjacent communities had been gentrified.
Gentrification Amid Urban Decline: Strategies for America's Older Cities, by Michael Lang, reports the process and impact (social, economic, cultural) of gentrification upon the “Darien Street” community of Philadelphia, Pennsylvania, an alley in the populous Bella Vista neighborhood. Darien Street was a “back street”, because it did not (and does not) connect to any of the city’s main arteries, and it was unpaved for most of its existence.
In its early days, Darien Street housed only Italian families, however, after the Second World War (1939–45), when the municipal government spoke of building a cross-town highway, the families moved out. In Darien Street, most of the houses date from 1885 (built for the artisans and craftsmen who worked and lived in the area), but, when the Italian Americans moved out, the community’s low-rent houses went to poor Black American families. Moreover, by the early 1970s, blighted Darien Street was at its lowest point as a community, because the houses held little property value, many were abandoned, having broken heaters and collapsed roofs, et cetera. Furthermore, the houses were very small—approximately 15 feet (4.6 m) wide and 15 feet (4.6 m) deep, each had three one-room stories, and the largest yard was 8 feet (2.4 m) deep. Despite the decay, Darien Street remained charmed with European echoes, each house was architecturally different, contributing to the street’s community character; children were safe, there was no car traffic. The closeness of the houses generated a closely-knit community located just to the south of Center City, an inexpensive residential neighborhood a short distance from the city-life amenities of Philadelphia; the city government did not hesitate to rehabilitate it.
The gentrification began in 1977, the first house rehabilitated was a corner property that a school teacher re-modelled and occupied. The next years featured (mostly) white middle-class men moving into the abandoned houses; the first displacement of original Darien Street residents occurred in 1979. Two years later, five of seven families had been economically evicted with inflated housing prices; the two remaining families were renters, expecting eventual displacement. In five years, from 1977 to 1982, the gentrification of Darien Street reduced the original population from seven Black American households and one white household, to two Black households and eleven white households. The average rent increased 488 per cent—from $85 to $500 a month; by 1981, a house bought for $5,000 sold for $35,000. Of the five Black households displaced, three found better houses within two blocks of their original residence, one family left Pennsylvania, and one family moved into a public housing apartment building five blocks from Darien Street. The benefits of the Darien Street gentrification included increased property tax revenues and better-quality housing. The principal detriment was residential displacement via higher priced housing.
Cambridge, Massachusetts -- a satellite of Boston across the Charles River -- is a blue collar town overlain with elite universities Harvard and M.I.T.. The local working-class culture is heavily Irish American and considerably alienated by both the White Anglo-Saxon Protestant elite that is these universities' historic clientele, but also intolerant of various minorities that elite universities have recruited beginning in the 1960s.
Cambridge is an interesting example because it embodies many of the seemingly contradictory forces involved in gentrification. For instance, populist politician Louise Day Hicks ably represented a large segment of this population in opposition to racial integration through court-mandated busing, but the considerably more liberal Kennedys John, Robert and Edward were also strongly supported. The power dynamics in Cambridge are also exceptional. In most communities gentrification eventually results in the complete displacement of those with lower incomes, however in Cambridge there is a stalemate of sorts. Poorer residents prevail to an unusual extent because the university population is largely transient and effectively constrained by university admissions and faculty recruitment. In contrast, the blue-collar residents are more permanent and better able to organize and consistently pursue their interests resulting in a level of influence atypical for their socio-economic status.
The phenomenon called syrjäytyneiden akanvirta (stream of the marginalized) in Finnish, has begun at wider range in the beginning of 2000s, when living costs in larger growth center cities have grown. The social support is not large enough to live in bigger cities when housing costs rise because housing situation is hard in the cities. Marginalized people have also many problems in living, so there is a constant fear of eviction from municipality-owned public housing. People who are poor and suffer from many problems of controlling their lives, move out to cheap private-owned housing very far away, where living is cheap. There are a number of businessmen, who buy old school buildings and renovate them to housing. The businessmen then offer these apartments as "a place of last resort" for "difficult" cases, that municipalities are reluctant to take into public housing apartments. Even the most marginalized people are welcomed to this kind of housing.