Research & reports

MDRC · MDRC · United States

A project page for ABLE (Adolescent Behavioral Learning Experience) at New York City's Rikers Island, the first US social impact bond. Goldman Sachs invested $9.6 million over four years, backed by a $7.2 million guarantee from Bloomberg Philanthropies. The programme served 16- to 18-year-olds, a group with a recidivism rate near 50 per cent within a year and more than 200 additional days in jail over six years, against a New York City incarceration cost above $85,000 per person per year. Cognitive behavioural therapy was cited as capable of cutting recidivism by up to 25 per cent, and the payment threshold was set at a 10 per cent reduction; a pilot ran February–June 2012 and full implementation from September 2012 to August 2015, with Moral Reconation Therapy delivered by The Osborne Association and Friends of Island Academy.

· Wikipedia · Global

The GIIN is a New York nonprofit founded in September 2009 by Amit Bouri and Antony Bugg-Levine, publicly unveiled on 25 September 2009 by Bill Clinton at the Clinton Global Initiative. It exists to scale and professionalise impact investing, running conferences and market research and managing the IRIS impact-measurement standards (launched 2009, succeeded by IRIS+ in 2019) and the Operating Principles for Impact Management. It had 421 member organisations as of June 2025, revenue of $16,484,237 and total assets of $16,968,824 in 2022, and 186 companies across 40 countries had signed the Operating Principles as of March 2025.

Zhao H., Wardropper C.B., Cao H., Campbell C.G., Chang N.-B., Qiu J. · npj Urban Sustainability · United States (South Florida)

A University of Florida (UF/IFAS) study of where public support for urban agriculture actually comes from, combining a survey of 1,000 adults across Miami-Dade, Broward and Palm Beach counties (in English and Spanish) with AI-assisted analysis of thousands of US news stories over the past decade. Support is not monolithic: different behaviours have different drivers. A sense of community connection predicts financial donations; hands-on gardening experience predicts volunteering; a sense of shared responsibility predicts buying local produce and backing policy. News interest has risen especially since COVID-19, and is strongest in Florida and West Coast states. The authors conclude that outreach tailored to the specific behaviour being sought works better than one uniform message.

Kremer, Peleg, Borowiak, Craig, Scolio, Madeline · Journal of Agriculture, Food Systems, and Community Development · 米国（ペンシルベニア州フィラデルフィア）

US community gardens embody a conundrum: vital to community well-being and integral to urban social infrastructure, yet profoundly vulnerable through insecure land tenure, fragmented policy support and systemic disinvestment. This reflective essay examines the Philadelphia Garden Data Collaborative (PGDC), a multistakeholder initiative documenting, protecting and advocating for community-managed green space, from the authors' position as participant researchers. It traces the shift from grassroots mapping to coordinated data stewardship, which enabled both emergency interventions (such as preventing sheriff-sale evictions) and long-term preservation strategies, and examines the ethical dilemmas of collecting sensitive community data where bureaucratic neglect has rendered gardens invisible and where visibility can expose them to new risks. It concludes that data can strengthen advocacy and inform policy, but must be coupled with secure tenure mechanisms and sustained public investment.

Bundesverband der Kleingartenvereine Deutschlands (BKD) · Bundesverband der Kleingartenvereine Deutschlands (BKD) · Germany

The national statistics page of the German federation of allotment garden associations (BKD). It gives the base figures — 867,092 plots, 44,000 hectares, an average plot of 370 square metres — along with the three-tier structure of roughly 13,000 clubs, 502 district federations and 20 state federations, membership by state, and a ranking of plots in the 15 largest cities (Berlin about 66,000, Leipzig 39,000). The nationwide average wait for a plot is three years, rising to seven in Berlin and eight in Hamburg. It also shows the skew by which the eastern states excluding Berlin, holding 15 per cent of the population, contain more than half of all allotments.

VGT Gartenfreunde Treptow e. V. · VGT Gartenfreunde Treptow e. V. · Germany

A source page in which the Berlin-Treptow garden association explains the Allotment and Small-Lease Ordinance of 31 July 1919 clause by clause. Section 1 put the rent for non-commercial horticultural land in the hands of the lower administrative authority, to be set in light of local conditions and land values after consulting agricultural and horticultural experts. Section 3 barred the landlord from terminating the lease, gave the holder a right to convert a loan for use into a lease, and a right to demand renewal once a term expired. Under section 4 an allotment office was set up in the Treptow district administration, which lasted until 1938. The association's 1948 statutes, the page notes, still referred back to the 1919 ordinance.

· Wikipedia (Deutsch) · Germany

The article on the history and scale of Germany's national allotment federation. Founded on 21 August 1921 as the Reich federation of German allotment associations, it later became the Bundesverband Deutscher Gartenfreunde and took its present name on 9 September 2023. It now covers more than 13,000 clubs and 20 state bodies, some 900,000 plots on 44,000 hectares used by around five million people — an area equal to 0.25 per cent of Germany's agricultural land. The article also carries the historical figures for 1938: one million members on 45,000 hectares, producing 350 million kg of fruit and 300 million kg of vegetables.

· Wikipedia (Deutsch) · Germany

The article on the VKSK, East Germany's national allotment organisation. Founded in Leipzig on 29 November 1959, it held the exclusive right to establish allotment sites. Membership stood at about 850,000 in 1962 and reached roughly 1.5 million by 1988. An extraordinary congress on 27 October 1990 resolved to dissolve the body with effect from 31 December 1990, and its gardeners and clubs passed into the all-German federation that followed.

Landesverband Berlin der Gartenfreunde e. V. · Landesverband Berlin der Gartenfreunde e. V. · Germany

The Berlin state federation of garden friends tracing its own history. It counts roughly 40,000 'Pflanzer' in Berlin between 1890 and 1910 and places the origin of today's federation in the April 1901 union of all planter associations of Berlin and its surroundings. After a series of First World War emergency decrees capped rent increases and obliged municipalities to provide land for cultivation, the Allotment and Small-Lease Ordinance of 31 July 1919 imposed rent control, banned leasing for profit and allowed land to be secured compulsorily. On 20 October 1919 the board of Berlin's colonists voted to rename their body the central federation of German allotment associations; by 1929 the Berlin provincial federation had 66,570 members, and that year Rehberge in Wedding opened as what the page calls Germany's first permanent allotment colony.

Karasungur S., Yavaş M. · Land Use Policy · Türkiye (Erzurum)

A paper that frames urban agriculture as a land-use policy instrument for protecting peri-urban agricultural land from urbanisation, analysed on a grid basis for Erzurum, Türkiye. Its angle is to treat urban agriculture not only as growing food in the city but as an institutional means of restraining farmland conversion. Note: this entry is written from the paper's bibliographic record and title; see the article itself for its figures and conclusions.

Bundesverband der Kleingartenvereine Deutschlands (BKD) · Bundesverband der Kleingartenvereine Deutschlands (BKD) · Germany

The national allotment federation's own history page. It sorts the nineteenth-century origins into six lines — poor gardens, factory gardens, Red Cross workers' gardens, the Berlin arbour colonists, gardens of the natural-healing movement and the Schreber gardens — and states that these lacked state legitimation and legal rules, with the absence of termination protection and the head-tenant system (Generalpächtersystem) in particular obstructing lasting protection. It records the passage of the Kleingarten- und Kleinpachtlandordnung by the National Assembly in Weimar on 31 July 1919, which banned commercial head-leasing and required rents to be fixed; the 1909 founding of the central federation; the Reich government's 1916 establishment of a central office for vegetable growing in allotments; the founding of the Reich federation of German allotment associations on 14 August 1921 at the second Reich allotment congress in Bremen; the Nazi-era Gleichschaltung; the post-war split into the VDK (Bochum, 1949) in the West and the VKSK (Leipzig, 1959) in the East; the 1973 renaming to BDG; and the renaming to BKD on 9 September 2023.

Bezirksamt Pankow von Berlin · Bezirksamt Pankow von Berlin (berlin.de) · Germany

An exhibition text in which Berlin's Pankow district office traces the history of allotment sites in the district. It describes the spread of Red Cross workers' gardens in the early twentieth century and their consolidation in 1906 into the Verband deutscher Arbeitergärten vom Roten Kreuz under Alwin Bielefeldt (1857–1942); the head-tenant (Generalpächter) system common around the turn of the century, in which land was leased and sublet with contracts often running for a single year; and the Kleingarten- und Kleinpachtlandordnung of 31 July 1919, which gave legal protection and prohibited head-leasing. On the arbour colonists it records the first permanent municipal lease in Blankenburg on former sewage fields in 1910 and the 1911 formation of a unified federation of arbour colonists of Berlin and surroundings, and cites a 1912 survey finding that 70 per cent of Berlin schoolchildren had never seen a sunrise and 54 per cent no sunset. For the GDR period it notes the founding of the VKSK in 1959, more than a million members by 1988 and its dissolution on 27 October 1990; more recently, that of Berlin's 900 allotment sites roughly 600 were given permanent protection and about 160 only time-limited protection.

· Wikipedia (English) · Germany

The article on the German food crisis of 1916–17 during the First World War. It states that the Allied blockade reduced food supplies by 33 per cent and that the civilian diet fell to 1,560 calories a day by the summer of 1917 and to 1,000 calories a day in winter, against the 3,000 calories said to be needed by a healthy adult male. The name comes from the substitution of fodder swedes (turnips) for the failed potato crop. Female mortality is given as rising 11.5 per cent in 1916 and 30 per cent in 1917 against pre-war rates, and the historian G. J. Meyer is cited, quoting a Berlin physician, for the claim that eighty thousand children died of starvation in 1916. The historian Avner Offer is cited for the estimate that one-fifth to one-third of food could be obtained only through illegal channels.

Deutsche UNESCO-Kommission · Deutsche UNESCO-Kommission · Germany

The German UNESCO Commission's page on the Berlin Modernism Housing Estates, inscribed as World Heritage in 2008. It lists the component estates: Gartenstadt Falkenberg (built 1913–1916), Siedlung Schillerpark (1924–1930), the Großsiedlung Britz or Horseshoe Estate (1925–1930), Waldsiedlung Zehlendorf (1926–1932), Wohnstadt Carl Legien (1928–1930), Weiße Stadt (1929–1931) and Großsiedlung Siemensstadt (1929–1934). Alongside the 2008 inscription it records that the Waldsiedlung Zehlendorf was added in July 2026; that estate has more than 1,900 dwelling units on 70 hectares. The architects named are Bruno Taut, Martin Wagner, Walter Gropius, Hans Scharoun, Hugo Häring and Otto Rudolf Salvisberg.

Landesdenkmalamt Berlin · Landesdenkmalamt Berlin (berlin.de) · Germany

A short notice issued by the Berlin State Heritage Office on 27 July 2026. It reports that on 26 July 2026 the 48th session of the UNESCO World Heritage Committee, meeting in Busan, South Korea, inscribed the Waldsiedlung Zehlendorf as the seventh component of the World Heritage site 'Berlin Modernism Housing Estates'. The estate was built between 1926 and 1932 by the housing cooperative GEHAG and comprises 1,917 dwellings — 1,108 in multi-storey blocks and 809 single-family houses. The architects were Bruno Taut, Hugo Häring and Otto Rudolph Salvisberg, with the open spaces designed by Leberecht Migge and Martha Willings-Göhre. It lies around the U-Bahn station Onkel Toms Hütte on line U3 and along Argentinische Allee in the Steglitz-Zehlendorf district. The nomination process began in 2021.

Rduch Paulina, Hodor Katarzyna, Wilkosz-Mamcarczyk Magdalena · Cities · ポーランド・チェコ

A study of Katowice (Poland) and Brno (Czech Republic) examining how family allotment gardens function as greenery in city centres, together with the legal regulations that govern them. Drawing on statistical and cartographic data, it shows a downward trend in the area of allotment gardens within cities.

Oyewole Michelle T., Pellow David N., Cassels Susie · Environmental Justice · 米国

A study measuring soil lead by X-ray fluorescence at 31 Brooklyn public schools with active garden programmes, sampling both garden beds and adjacent school grounds. Proximity to 306 known environmental hazard sites was mapped geostatistically and combined with demographic data and soil-management surveys. Of the samples, 42% exceeded the US EPA's minimum screening level for child-accessible soils near known lead sources (100 ppm); garden soils showed lower average lead concentrations than adjacent school-ground soils. The authors argue that soil lead in schools, and the disparities in it, have received far less attention than lead in paint and water.

Ricardo Robins · Fundación Rosa Luxemburgo (Oficina Buenos Aires) · Argentina

A reported feature tracing the origins of Rosario's Urban Agriculture Programme (PAU) through interviews with founder Antonio Lattuca: the first community garden in the Saladillo Sur neighborhood in 1987, the 1990 municipal ordinance creating the Community Gardens Programme, and the PAU's formal launch in 2002. It reports the programme today spans 12 parks and community gardens across roughly 40 hectares, with over 150 families harvesting about 650,000 kg of agroecological vegetables a year, and profiles the Tablada Park Garden (opened 2008, 3 ha, 20 workers).

Municipalidad de Rosario · Municipalidad de Rosario · Argentina

A Rosario municipal procedural page describing a free training-visit programme for institutions and civic organizations to tour the city's gardens and Park Gardens and learn about agroecological practices, run by the Productive Spaces Coordination unit under the Social Economy Sub-secretariat. Appointments are booked at six district municipal centers on Wednesdays 9:00-13:30, with the programme's legal basis cited as Decree 2561/2004 and Ordinance 9044/13.

Aguiari I. · Agriculture and Human Values · イタリア

Debates on food and agriculture have long noted the depoliticising pull of neoliberal governance, technocratic regulation and consumer-oriented solutions. Collective action in grassroots agrifood initiatives is well studied, but how politicisation actually emerges is not. Treating the political as an ever-present dimension of social relations, the author uses political semiotics to trace how politicisation and depoliticisation unfold in everyday communication, drawing on participatory mind-mapping workshops co-created with three community agriculture initiatives in Italy. Politicisation is encouraged where relational interaction, contextual interpretation, symbolic expression and an orientation toward collective action reinforce one another.

Nkrumah B. · Urban Science · アフリカ（都市部・系統的レビュー）

A systematic review of the irony between abundant arable land and persistent hunger in African cities. It asks why a disproportionate share of urban residents do not produce their own food, even as food insecurity rises with heavy reliance on market-bought food, high poverty and rapid urbanisation, screening peer-reviewed literature via PRISMA and five inclusion benchmarks to clarify the debate on low uptake of urban agriculture.

Rao X., Zahid A., Ye X., Jain D., Duffield N. · Urban Informatics · 国際（論考）

A Perspective arguing that controlled environment agriculture (CEA), driven by venture capital and profit-maximising imperatives, has delivered limited scalability, narrow crop diversity and minimal engagement with spatial equity — the fair distribution of food infrastructure across urban geographies. It calls for repositioning CEA not as a standalone technological fix but as a component of urban infrastructure delivering co-benefits for food justice, public health and environmental resilience.

Hinch J. · Southeastern Geographer · 米国フロリダ州タンパベイ

This study builds an equity-focused, GIS-based multi-criteria decision analysis model integrating socioeconomic, logistical and environmental variables to assess community garden suitability across census tracts in Tampa Bay. High-suitability tracts cluster somewhat in Hillsborough and Pinellas Counties, existing gardens align moderately with modelled suitability, and the paper shows both the utility and the limits of spatial models in equitable urban agriculture planning.

Noxolo B.M., Kanosvamhira T.P. · Urban Agriculture & Regional Food Systems · 南アフリカ・ケープタウン（低所得地区）

Surveys and interviews assess whether hydroponics, of interest because dense settlements leave little space, is actually viable in Cape Town's low-income urban areas — deliberately supplementing a literature skewed towards Global North cities. Farmers perceive benefits in improved yields, water conservation and efficient land use, all valuable in a water-scarce, space-constrained city, but high setup costs and limited government support remain significant obstacles. Drawing on urban political ecology, the paper argues these financial and institutional barriers are rooted in historically produced inequality and ongoing capitalist dynamics of urban development. It concludes that while hydroponics has potential as a sustainable alternative, its high costs hinder broader applicability, and it is not yet a viable large-scale route to food security where resources are unequally distributed; supporting actors must first address financial feasibility and local expertise.

Darrow S., Kathi S., Liebe R., Cline L.L., Moss J.Q. · Urban Agriculture & Regional Food Systems · 米国オクラホマ州（農村・都市・近郊）

Oklahoma's specialty crop sector is in decline — vegetable operations fell from 799 in 2007 to 482 in 2022 — yet regional fruit and vegetable producers remain the primary supply foundation for farmers' markets, food hubs and direct retail serving urban and peri-urban communities, so producer viability is itself an urban food access and public health concern as food deserts expand. Five semi-structured focus groups with 29 experienced producers from rural, urban and peri-urban Oklahoma were analysed by open coding thematic analysis in NVivo, with saturation confirmed iteratively and rigour established through member-checking, peer review of codes and field note triangulation. The 180 initial codes were organised into 10 parent codes and three themes: the countercultural philosophy of production, the lack of accessible resources, and industry barriers preventing development — compounding disadvantages at cultural, institutional and structural levels. The authors call for a statewide local food system plan, a growers' association and dedicated local-food-system extension roles.