What the evidence says

The wiki

This wiki is not intended to be read like a review article that relates and discusses in detail a large body of literature on a subject. Instead the evidence is brought together, categorised, and presented in a raw and impartial form in the hope that others will digest, utilise, investigate further, and hopefully add to this resource with more and better evidence in the future. In its pages similar studies are (as far as possible) grouped together. Each entry is briefly discussed in terms of the aims and methods underpinning the research, with key findings drawn out as they relate to the value of place quality. Wherever, possible links to the original sources of evidence are provided to allow users to refer to the evidence directly in their work.

The headlines

The intention when developing the wiki was to compile the evidence rather than to develop definitive positions on what the evidence says. But having gone through this process, it would be remiss not to draw out any overarching conclusions from the evidence collected in the wiki. Three key conclusions can be drawn:

Overwhelming evidence: The first reflects the overwhelming nature of the evidence, the vast majority of which points in the same broad direction, that better place quality adds value economically, socially and as regards health and environmental outcomes. Indeed the impacts of place are profound, contribute benefits to society over short, medium and long-term time horizons, and reverberate throughout the lives of citizens across all socio-economic strata and globally.

Wide-ranging benefits: Second, whilst the different types of value listed under each of the sub-headings in this wiki:

May not be directly comparable (e.g. mental well-being versus return on a property investment)
Often flow differentially to different stakeholders and over different time horizons (e.g. short-term profit to developers versus long-term health benefits to society)
Sometimes do not accrue to those who paid for them at all (e.g. the impact of street trees may not be truly felt until they are fully grown)

Nevertheless all are important and can be considered together as a varied and ever changing package of benefits that potentially flow from the quality of place.

A basic necessity of life: Third, in a context where the governance of urban areas is increasingly a shared endeavour encompassing critical inputs from public, private, third and community sectors, such a shared perspective on the importance of place quality is all the more important and (where it exists) is very powerful in its impact. Place quality is not a luxury to be afforded when things are good or only for the wealthy. Instead it is a basic necessity of urban life with profound impacts on the lives of citizens. It is so important to our basic well-being that it should be the expectation of all.

More specific conclusions relating to the four policy arenas covered by the wiki – health, social, economic and environmental – are included at the start of those sections of the wiki.

About place quality

As well as revealing much about how place quality impacts on the different forms of value explored in this wiki, the collective evidence also reveals a good deal about the sorts of places that deliver that value, and more specifically about the qualities of the built environment that do this:

There is a VERY strong positive association between place derived value of all types and:

Greenness of the environment (notably the presence of trees and grass, water, and open space – the latter if of good quality)
The mix of uses (notably the diversity of land uses within a neighbourhood)
Low levels of traffic
Walkability and bikeability of places (derived from their strategic street-based connectivity and the quality of the local public realm)
The use of more compact (less sprawling and fragmented) patterns of development
Connection into a good public transport network.

There is a strong positive association between place derived value of all types and:

Visual permeability
Sense of place (distinctiveness)
Pedestrian scale (of streets and buildings)
Façade continuity
Natural surveillance (the creation of defensible space)
Presence of street level activity / background movement
Good street lighting
A denser street network (urban grain)
Low traffic speeds and neighbourhood noise
Presence of attractive / welcoming / comfortable / adaptable public spaces
Positive (sociable) public/private threshold features
Integration of built heritage, natural features and a diverse ecosystem
Perceived architectural quality and beauty generally.

About place inferiority

Collectively the evidence revealed some characteristics of the built environment to be systematically inferior:

There is a particularly strong negative association between place derived value of all types and:

Car dependence and extensive forms of suburbanisation
Absence of local green space
Too much very local permeability
The presence of rear parking courts and other segregated areas
Poor maintenance / dilapidation (including of green spaces)
A sense of over-crowding in residential areas
Presence of unfavourable food stores
Higher traffic loads and speeds, wider carriage-way widths, or elevated highways.

Conflicting evidence

On some matters the evidence was unclear or conflicting, with results that attribute both positive and negative outcomes to certain qualities. The evidence was conflicting on the relative merits of:

Different architectural styles
Higher versus lower densities of development (within the health evidence, and as regards sociability versus perceived crime)
The impact of extreme densities (as regards evidence on carbon reduction, social welfare, and ecological richness)
High-rise living
Street length and pedestrian connectivity (within the evidence on health versus crime)
The use of cul-de-sacs (within the evidence on crime and safety and as regards property value, sociability and children’s play)
Vehicle / pedestrian separation
Use of shared spaces (as regards the evidence on actual and perceived safety)
The economic impact of the proximity of retail to residential properties.

A ladder of place quality

It is possible envisage these different qualities as sitting on a ladder. The ladder climbs from those place qualities that should be avoided at all costs when designing new development (because of their very likely negative health, social, economic and environmental impacts); to those about which the evidence is still inconclusive (and where we should be careful not to be too prescriptive in policy and guidance).

Next come place qualities that are strongly associated with positive outcomes of all types (and which should be the aspiration of built environment policy and development-related decision-making). Finally we have a limited number of qualities that are fundamental and which should be required in new development as a means to maximise place value through good design.

For further discussion of the ladder, see:

Carmona M (2018) Place value: place quality and its impact on health, social, economic and environmental outcomes, Journal of Urban design, https://tandfonline.com/doi/full/10.1080/13574809.2018.1472523

And for a pamphlet designed for non specialist audiences, Place Value & the Ladder of Place Quality can be downloaded here.

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