Home Track

Housing that meets the housing needs of the community that are not met by the housing market.  Affordable housing includes social rent, affordable rent and intermediate housing (e.g. shared equity or shared ownership). Affordable homes are provided at below market prices, and restricted to certain types of household.

A body set up by a local authority to take over the day-to-day running of their properties and bring social housing up to a decent standard, separating the landlord role from their wider strategic function in order to improve the quality and management of their housing.

Asset-backed securities are debt instruments secured against assets or cash flows from items such as car loans, credit card debt, mortgage loans, aircraft leases or royalty payments. The assets are pooled or bundled together and used as collateral for the issue of debt instruments in a process known as securitisation. A special purpose vehicle (SPV) is formed to carry out the securitisation and pay back the company that owned the assets.

A form of social housing, involving homes being made available at a rent level of up to 80% of market rent (inclusive of service charges); the principal product available as new supply through the Affordable Homes Programme in 2011-15.

The amount of money a tenant has not paid to the landlord or mortgage lender on time.

The most common form of private rented sector tenancy agreement. This fixed term agreement grants a degree of security of tenure to the tenant but allows the landlord to charge market rent and to regain possession on certain grounds, laid out in the Housing Act 1988.

A model which uses one or more mathematical techniques to provide an estimate of value of a specified property at a specified date, accompanied by a measure of confidence in the accuracy of the result, without human intervention post-initiation. 

See Desktop Valuation

NB: Any modification or manipulation by a valuer of an AVM output or of the comparables selected by an AVM separates the subsequent output from the integrity of the fully automated process which is a defining feature of an AVM. Hence, “AVM-Assisted Valuations”, “Valuer-Assisted AVMs” and similar expressions fall within the definition of a Desktop Valuation. For clarity it is recommended that these expressions should be avoided.

An estimate of property value as calculated by an AVM.

Automated Valuation Model which uses one or more mathematical techniques to provide an estimate of value of a specified property at a specified date, accompanied by a measure of confidence in the accuracy of the result, without human intervention post-initiation. 

Annual interest rate set by the Bank of England on which UK commercial banks base their lending and deposit rates.

The Basel Accords on banking regulation, also known as Basel I and Basel II, were issued by the Basel Committee on Banking Supervision in 1988 and 2004. They are called the Basel Accords as the Committee normally meets at the Bank for International Settlements (BIS) in Basel, Switzerland. Basel I focused mainly on credit risk and became legally enforceable in G10 countries in 1992. Its principles have since been adopted by most countries. Basel II set standards on the amount and use of capital that banks require in order to deal with the various risks they face.

Choice-based lettings are a way that some local councils and housing associations let their properties.

The common feature is that once someone has registered they are looking for housing, they have to bid for properties that become available - rather than waiting to be offered one. Based on their circumstances they will be awarded a 'priority rating', and this will determine who gets a property if several people bid for it.

A levy that allows local authorities in England and Wales to raise funds from developers undertaking new building projects in their area. The money can be used to fund a wide range of infrastructure that is needed as a result of development. This includes new or safer road schemes, flood defences, schools, hospitals and other health and social care facilities, park improvements, green spaces and leisure centres.

A measure of performance of an AVM.  In mathematical terms, COD is the average absolute deviation of ratios in a model from the median ratio of that model.  In Ratio Studies, COD is the average percentage deviation from the median ratio.

NB: WARNING: In statistics texts, COD stands for Coefficient of Determination – a name given to the R-squared value.  This is different from the Coefficient of Dispersion described here.

A measure of performance of an AVM. A statistical measure of the dispersion of data points in a data series around the mean: calculated by dividing the Standard Deviation by the mean of the distribution.

A property used by in the valuation process as evidence in support of a valuation of a property. The description of the comparable in a valuer’s justification of value will depend on the nature and complexity of the valuation being undertaken but will typically include its address, some financial information such as sale price or rent agreed at a particular date and some indication of the similarities with, or differences from, the property being valued.

A set of Comparables in support of a valuation.

The Spending Review is a Treasury-led process to allocate resources across all government departments, according to the Government's priorities.  Spending Reviews set firm and fixed spending budgets over several years for each department.  It is then up to departments to decide how best to manage and distribute this spending within their areas of responsibility.

Legal order that allows some public bodies to take control of land or property without the consent of the owner, in the interest of the public good. The owner is entitled to compensation, which is usually at least the market value of the property.

For a given Confidence Level, the range within which one can conclude that a measure of the population lies.

A statistically derived figure (usually given on an AVM provider’s proprietary scale) that gives a measure of confidence in the accuracy of the AVM estimate. The degree to which the Confidence Level correlates with the accuracy of the AVM estimate of valuation when compared with the Reference Value is an important measure of the performance of the AVM.

The probability that a Confidence Interval will include the population measure; commonly 90, 95, or 99 percent. A 95 percent Confidence Interval would mean, for example, that one can be 95 percent confident that the population measure (such as the median or mean appraisal ratio) falls in the indicated range.

See Confidence Level.

See Confidence Level.

The possibility that a mortgage holder or other borrower will default and fail to pay the principal and interest on a loan when due. Credit risk plays a major part in setting the interest rate and terms on a loan. For example, only those with near perfect credit ratings (low perceived credit risk) are eligible for high loan-to-value mortgages at present.

The process of refining data associated with potential AVM Comparables with the aim of improving its accuracy.

The process of examining recorded data to ensure that each element of data is reasonable and is consistent with others recorded for the same property.  It also refers to the exclusion of non open market sales from the sales set which is to be used in Model Calibration.  Data editing, which may be done manually or by computer, is essentially a mechanical process, distinct from verifying the correctness of the recorded information by inspecting the property.  See also Hard Edit; and Soft Edit.

A variable, such as open market value, which is predicted by the values of other variables, such as floor area, number of rooms, number of bathrooms, etc. Such a variable is said to depend on other (Independent) Variables.

An estimate of value of a property completed by a Chartered Surveyor without undertaking a physical inspection of the subject property, based on local knowledge, personal experience and supported by Comparable Evidence, which may or may not incorporate data from property databases, including AVM estimates of value.

The degree to which data are distributed, either tightly or loosely, around a measure of central tendency. Measures of dispersion include the average deviation, Coefficient of Dispersion, Coefficient of Variation, range, Variance and Standard Deviation.

Economic capital is the amount of risk capital held by a financial services company to enable it to survive any difficulties such as market or credit risks.

The amount is determined internally by the company or by shareholders, often using a measure of portfolio risk such as value at risk (VAR). VAR describes the probability of losing more than a given amount of assets, based on a current portfolio.

The number of successfully returned AVM results which also meet additional user-defined criteria, divided by the total number of requests submitted by the user, usually expressed as a percentage.

NB. Effective Hit Rate is not measured by dividing the number of successfully returned AVM results which also meet additional user-defined criteria by the number of successfully returned AVM results. This produces an artificially high result.

Contrast with Hit Rate.

A residential property that has been uninhabited for a significant period of time, usually a minimum of 6 months.

Equity loan scheme designed to help first-time buyers into home ownership. FirstBuy support is offered through equity loan funding of up to 20% of the purchase price of a new build home split between the HCA and the house builder. The purchaser is required to raise funding of at least 80% of the purchase price of the property, usually through mortgage finance.

A tenancy that lasts for a fixed period of time. The HCA expect housing associations to offer affordable rent properties on fixed term tenancies of a minimum of 2 years.

A lender's postponement of foreclosure in order to give the borrower time and opportunity to make up for overdue payments.

With respect to difference between the AVM Valuation and the Reference Value, the Forecast Standard Deviation is the predicted (forecast) Confidence Interval at a Confidence Level of 68% (i.e. one Standard Deviation).

A database management system used to store, retrieve, manipulate, analyse and display spatial information.

One type of computerised mapping system capable of integrating spatial data (land information) and attribute data among different layers on a base map.

The task of defining the goals and standards of an organisation and ensuring that there are effective management and other structures that will enable the organisation to achieve those goals and standards.

Area of land around towns and cities where development is not permitted.

Hedonic pricing attempts to take observations of the overall goods or services and obtain implicit prices for the goods and services. Prices are measured in terms of quantity and quality. Calibration of the attribute components is performed statistically by regressing the overall price onto the characteristics.

The number of AVM results returned where there is a valuation estimate and a Confidence Level divided by the total number of requests submitted, usually expressed as a percentage. Contrast with Effective Hit Rate.

A range of government-backed products and services from the HCA designed to help first-time buyers buy houses through devices such as shared equity, shared ownership, and other forms of low cost homeownership.

Acts as a first point of contact for applicants seeking to buy a home through the HCA’s HomeBuy affordable home ownership products. Agents establish whether applicants meet eligibility criteria before assessing applicants’ financial circumstances to ensure that they can afford home ownership longer term. HomeBuy Agents also advise applicant on their housing options and assist them to make the right choice to meet their housing needs.

Independent societies, bodies of trustees or companies established for the purpose of providing low-cost social housing for people in housing need on a non-profit-making basis. Any trading surplus is used to maintain existing homes and to help finance new ones. See Registered Provider.

A government benefit for tenants on low incomes which pays all or part of the rent and service charge for a property. HB cannot be used to cover the cost of a mortgage or any other home loan.

Local authorities with housing stock are required to record all income and expenditure in relation to these dwellings in their Housing Revenue Account (HRA). The account is kept separate or ring-fenced from other council activities.

A special, non-recurring charge taken to write down an asset with an overstated book value.

A variable whose value is not determined by other variables.  Contrast with Dependent Variable.

Linking regular income or payments, such as salaries and taxes, to the consumer or retail price index so that the amounts are adjusted for changes in the inflation rate.

Inflation is a persistent rise in the prices of goods and services. It can be caused by an increase in the money supply, by an increase in demand due to government spending or by a contraction in the supply of goods. Different types of inflation can be defined by their causes. Demand-pull inflation is caused by excessive demand in an economy, while cost-push inflation is caused by rising input costs. The achievement of a moderate rate of inflation is a primary goal of economic policy and central banks in many industrialised countries have been given policy independence in order to achieve it. Moderate inflation is common in many economies and can be regarded as relatively benign. If inflation falls to zero and an economy slips into deflation it can stunt economic growth.

Graphically, the point at which a line, such as a regression line, intersects the axis on which the dependent variable (e.g. property value) is represented; the value of the predicted variable when the value of all other values in the model is zero; the constant in the MRA equation.

The charge or the return on an asset or debt expressed as a percentage of the price or size of the asset or debt. It is usually expressed on an annual basis.

Housing at prices and rents above those of social rent, but below market price or rents. This includes: Shared Ownership, Equity Loans, Social HomeBuy and Affordable Rent.

A sub-market rental scheme where the rent is no more than 80% of local market rents.

The issue price is the price at which securities are first offered for sale.

Public sector workers, known as key workers, such as teachers, nurses and police are often entitled to, or prioritised for some forms of affordable housing. Many organisations are relaxing their definition of key workers to include any worker (public or private sector) who contributes to the local economy but earns a low income.

A portfolio of land help by developers, such as house builders, for building at a later date.

This is when a local authority transfers the ownership and management of all or part of their housing stock to a housing association.

The plural of liability; all financial claims, debts or potential losses against or incurred by an individual or an organisation.

The primary benchmark for short term interest rates globally. It is used as the basis for settlement of interest rate contracts on many of the world’s major futures and options exchanges and has recently been used as a barometer by the media to measure the health of financial monetary markets.

The ratio of the fair market value of an asset to the value of the loan that will finance the purchase.

Agreements between Government, the local authority and its major delivery partners, working through the local strategic partnership to facilitate local areas to focus on delivery of a limited number of key outcomes, agreed jointly between the local authority and the government office.

The administrative body that governs local services such as education, housing and social services. An umbrella term that could refer to any unitary authority or county, metropolitan or district council.

Local enterprise partnerships are locally-owned partnerships between local authorities and businesses that play a central role in determining local economic priorities and undertaking activities to drive economic growth and the creation of local jobs.

Rates set for different types of accommodation, which dictate the amount of housing benefit a tenant renting from a private landlord can claim. LHA rates are set by the VOA, and are set at the 30ieth percentile of open market rents. The rates vary according to number of bedrooms in a property and the broad rentl market area a property is in.

A social housing organisation set up to improve local authority housing. The idea is that a LHC will take over a local authority's stock and can then borrow private finance to improve the properties.

A voluntary agreement negotiated between local authorities and the Government with the aim of improving the delivery of local public services by focusing on targeted outcomes.

The LSP brings together local authorities, other public services, private, voluntary and community sector organisations and residents to improve local areas and services.

Proposed government policy that aims to devolve greater powers to councils and neighbourhoods and give local communities more control over housing and planning decisions.

The amount of funds that is lost by a bank or other financial institution when a borrower defaults on a loan. Academics suggest that there are several methods for calculating the loss given default, but the most frequently used method compares actual total losses to the total potential exposure at the time of default.

Of course, most banks don't simply calculate the LGD for one loan. Instead, they review their entire portfolio and determine LGD based on cumulative losses and exposure.

The percentage of lost principal when a loan is foreclosed.

A range of different schemes designed to enable those to purchase a property who couldn’t otherwise afford to do so. Shared ownership and shared equity are the two most common types of LCHO scheme.

The act of recording the value of a position or portfolio based on the day's closing price. Instead of being valued at the original purchase price, the portfolio is valued at its current worth, reflecting any profit or loss which is not yet realised but which would be if the position were sold immediately.

A rent based on the maximum amount on the open market.

Custody arrangement where a trust company, acting as a trustee, manages several trust properties as a single trust property for a group of associated trustors or firms.

A mortgage-backed security is a security backed by, or secured against, a pool or package of mortgage loans. Payments of principal and interest from the pool of mortgages are passed to the holder of the security.

A group of mortgages held as collateral for a mortgage-backed security. The securities issued represent shares in the pool. The mortgages in a particular pool have a similar maturity and interest rate and are on a similar class of property.

Government-backed product that aims to assist eligible homeowners to avoid repossession. There are two ways mortgage rescue can assist homeowners: Government Mortgage to Rent, whereby a homeowner sells their property to an eligible provider and becomes a tenant; and Shared Equity, where a homeowner sells part of their equity to an eligible provider but still remains the owner.

A government review of planning policy, designed to consolidate policy statements, circulars and guidance documents into a single concise National Planning Policy Framework.

A situation where a loan becomes worth more than the asset it is secured against.

The environment of a subject property that has a direct and immediate effect on value.

An area that is subject to the same, or similar, market forces.

A geographic area of properties sharing important location characteristics defined for purposes of market analysis or modelling (typically with fewer than several thousand properties). Broadly, in practical terms, a Neighbourhood is a contiguous area around a subject property from which a valuer would be most happy to select sales comparables. (All VOA usage).

A group of Neighbourhoods / Localities (not necessarily contiguous) which can be modeled together; i.e. where they are subject to similar market forces.  In practical terms, if the subject property is within one Neighbourhood, the other neighbourhoods in the neighbourhood Group are where a valuer would seek comparable sales if insufficient sales are available within the immediate neighbourhood.

Under government proposals communities will be able to develop a plan which, if it succeeds both at an independent examination and at a public referendum, can be adopted through a Neighbourhood Development Order that gives it statutory basis within the local development plan documents.

This mechanism enables communities to define specific developments or types of development which will have automatic planning permission without the need for any application to the local authority, as outlined in the Neighborhood Plan. For more complex cases they will be able to grant outline permission so that the right to develop would be established and only the details would need to be approved.

A government scheme designed to create an effective fiscal incentive to encourage local authorities to facilitate housing growth.  For every additional new build home built, the local authority will be paid a grant by central government equal to the average council tax for that property band for the following 6 years.

PPS3 sets out the national planning policies for housing, which regional planning bodies and local authorities will take into account in developing regional spatial strategies and local development frameworks. PPS3 underpins the delivery of the Government’s strategic housing policy objectives.

A collection of investments held by an individual investor or financial institution. They may include stocks, bonds, futures contracts, options, real estate investments, mortgages or any item that the holder believes will retain its value.

In relation to an AVM, the process of undertaking multiple valuations in a batch process.

The degree of likelihood that the borrower of a loan or debt will not be able to make the necessary scheduled repayments. Should the borrower be unable to pay, they are then said to be in default of the debt, at which point the lenders of the debt have legal avenues to attempt obtaining at least partial repayment. Generally speaking, the higher the PD a lender estimates a borrower to have, the higher the interest rate the lender will charge the borrower (as compensation for bearing higher default risk).

A Real Estate Investment Trust (REIT) is a vehicle that allows an investor to obtain broadly similar returns from their investment, as they would have, had they invested directly in property. The vehicle is a limited company (or a group of such companies), required to invest mainly in property and to pay out 90% of the profits from its property rental business as dividends to shareholders. REITs are exempt from tax on the income and gains from their property rental business.

The old definition of registered social landlord ("RSL") has been replaced with the concept of registered providers of social housing. All providers of social housing will now be listed on a register and will become a "Registered Provider" (RP). A distinction between this system and the old system of RSLs is that a provider of social housing can now be either a non-profit organisation or a profit-making organisation. Each body will be designated as one or the other upon being entered on to the register. RSLs automatically became non-profit registered providers under the new system.

A Housing Association or a not-for-profit company formerly registered with the Tenant Services Authority to provide social housing. RSLs registered with the TSA immediately prior to 01 April 2010 become Registered Providers (RPs).

Regulatory capital is the amount of risk capital held by financial services company to enable them to survive any difficulties such as market or credit risks.

The amount is determined by legislation or regulators.

To borrow money by having a second or bigger mortgage (loan) on your property, especially a house.

A second or bigger mortgage on your property, especially a house.

The act of paying back money previously borrowed from a lender. Repayment usually takes the form of periodic payments that normally include part principal plus interest in each payment. The other common method of repayment is a lump sum with interest at maturity.

The act of reclaiming property or goods from their owners who have defaulted on their payments for these property or goods.

These securities are backed by mortgages on residential properties. RMBS represent by far the largest section of the European asset-backed market.

A method for appraising the value of land. The value left after the cost of putting land to a particular use (such as building homes) is subtracted from the revenue generated from the land when it is in that use. For example a house builder assessing the value of a piece of land therefore has to estimate the value of the homes that can be built on the site and the cost of building them to derive a land value.

A resilience test, or stress test, is an analysis of the ability of a bank or insurance company to withstand major market movements. Certain scenarios are assumed such as a 100 percent rise in world oil prices, a 25 percent fall in share prices or a five percent rise in official interest rates. Calculations are then made to assess whether a firm could cope, whether it would have sufficient capital to cover its losses. If not, should extra provisions be made or should investment strategies be changed is questionned.

The most commonly used measure of inflation. Based on the prices of a ‘basket’ of goods and services intended to reflect a typical family’s spending.

The Right to Acquire (RTA) scheme was introduced by the Housing Act 1996 with effect from 1 April 1997. The scheme enables eligible housing association tenants living in qualifying properties to buy their rented home at a discount. RTA only applies to properties built or acquired by housing associations, both charitable and non charitable, with public funds from 1 April 1997 onwards. Properties transferred from a local authority to a housing association after 1 April 1997 are also eligible. Some properties are exempt from RTA including sheltered housing and homes located in small rural settlements.

The Right to Buy scheme allows social tenants in England and Wales to buy their council home at a discount. Discounts vary according to how long the purchaser has been a tenant and by region.

When you calculate how much risk there is not being paid if you supply a company in a foreign country with goods or services when a bank calculates how much risk there is of not being paid if it makes a loan to a foreign country when a check is made on a factory to see that it is operating safely.

The amount of risk an investor has taken on in a particular investment or a portfolio. Or to what extent a business could be affected by certain factors that may have a negative impact on earnings.

RMBS (Residential Mortgage-Backed Security)

These securities are backed by mortgages on residential properties. RMBS represent by far the largest section of the European asset-backed market.

RMBS (Residential Mortgage-Backed Security)

These securities are backed by mortgages on residential properties. RMBS represent by far the largest section of the European asset-backed market.

A contract entered into by a local planning authority and a property developer under section 106 of the Town and Country Planning Act 1990 under which the developer agrees to provide defined facilities as part of the proposed development. Such planning obligations are often used as a legally binding agreement between a local authority and developer to deliver affordable housing within a development.

The letting of a dwelling by a non-private landlord, usually a local council or housing association, under an agreement that allows security of tenure. Secure tenancies may allow tenants to remain in a property for life and also grant succession rights.

Securitisation is the process by which asset backed securities (ABS) are created. The assets to be securitised are sold to a special purpose vehicle (SPV), thus isolating the borrower from any claims for repayment. The SPV then issues bonds or other debt instruments which can be traded in the same way as any other security. The money raised by the issuance of the debt is used to pay the borrower for the assets. Mortgages, car loans and credit card loans can be securitised as can future royalties from a pop star's song portfolio.

A product where the purchaser of a property is offered an equity loan of up to 30% of the property value to assist with their purchase. The purchaser will then take out a mortgage to fund the rest of their purchase. Often there will be no or reduced interest charges on the loan. FirstBuy, HomeBuy Direct and MyChoice HomeBuy are examples of government sponsored shared equity schemes.

A low cost home ownership scheme (such as New Build HomeBuy) that allows purchasers to part buy/ part rent a property.  The purchaser will buy a share of the property (usually between 25% and 50% of the total property value) and then pay rent on the remaining share.  Purchasers can then increase or decrease their share of the property through staircasing.

Social HomeBuy (SHB) is a voluntary scheme which was introduced in April 2006. It enables tenants of participating local authorities and housing associations to buy a share of between 25 per cent and 100 per cent in their rented home. SHB helps in particular housing association tenants who do not have the Right to Buy or Right to Acquire, and social tenants who cannot afford outright purchase. Tenants receive a discount on the initial share purchased and on any additional shares they buy. This is equivalent to the Right to Acquire discount (between £9,000 and £16,000 - depending upon the local authority area in which the property is located), pro-rata to the share purchased.

Low cost rental accommodation and low cost home ownership as defined by section 69 of the Housing and Regeneration Act 2008. Aimed at people whose needs are not met by the commercial market.

Abbreviation of Special Purpose Vehicle. Sometimes referred to as a Special Purpose Entity (SPE). SPVs are entities created for a specific, limited and normally temporary purpose.

They are limited companies or partnerships to which the debt of another company is transferred. By transferring its debt off its balance sheet into an SPV a company is able to isolate itself from any risk that the debt might pose. SPVs are often used in the securitisation of loans or other instruments. For example, a bank may issue a mortgage-backed security (MBS), the income from which is derived from repayments from a pool of mortgage loans. The bank may wish to legally separate itself from the loans and does so by setting up an SPV and transferring the loans to it.

The process where owners of shared ownership properties can purchase additional equity in the property.

A statistical term which is the measure of Dispersion.

This refers to the transfer of ownership and management of local authority housing to a housing association or other managing organisation.

Strategic Housing Market Assessments provide information on the level of need and demand for housing for an area. A SHMA should estimate housing need and demand, determine how the distribution of need and demand varies across areas and consider future demographic trends, indentifying the accommodation requirements of specific groups such as homeless households, first time buyers, older people etc.

Strategic Housing Land Availability Assessments provide information on the opportunities that exist to meet demand for an area.  The SHLAA should asses the likely level of housing that could be provided if unimplemented planning permissions were developed, assess land availability, assess the quantum of housing that could be developed, identify site specific constraints limiting development and identify how constraints on particular site could be overcome.

Development that meets the needs of the present and doesn’t compromise the ability of future generations to meet their own needs.

Has the potential to produce good quality housing at a price that is affordable both in the short and long term. The concept of sustainability (meeting the needs of today without compromising the needs of future generations) has been around for a number of years; however its application to housing has been slow.

A truly sustainable housing project should incorporate economic, social and environmental issues in the planning and design stages with the aim of providing a building that is affordable, accessible and environmentally sound.

The range of values that can be supported by comparable evidence for a particular property type on any given site. SVRs are a principle output of the Developer Pricing Analytics Report.

Supportable Valuation Range - The range of values that can be supported by comparable evidence for a particular property type on any given site. SVRs are a principle output of the Developer Pricing Analytics Report.

Guideline rents for social rented housing determined by a formula referencing local house prices and local earnings. 

With reference to housing, tenure refers to the status of someone who occupies housing. The principal forms of housing tenure are freehold, a tenancy, leasehold and a license.

Title is the legal term denoting the right to ownership of a property and the Title Deeds are the legal documents showing who owns a property. They don't just show who owns the property now but are the collected legal documentation of past transfers of ownership as well.

Title deeds may contain evidence of mortgages, marriage settlements, wills, sales deeds and descriptions of buildings, including changes of use, alterations and extensions. There may also be clauses in the title deeds limiting what may or may not be done on the property, from pet ownership to restrictions on commercial usage.

The process of changing the values and definitions of one or more variables so as to make them more useful for further analyses. If market value changes with plot size, for example, a valuable transformation would be to change frontage and depth to plot size, and if market value does not change proportionally with size, a valuable transformation might be to use the square root or logarithm of plot size.

This is a subjective term. The expression Reference Value should always be used in the context of AVM performance (see Reference Value).

Mortgage underwriting is the process a lender uses to determine if the risk of offering a mortgage loan to a particular borrower under certain parameters is acceptable.

Government model for reform of the welfare system. The universal credit is intended to simplify the benefits system by replacing a range of different benefits with one single payment. This will be based on income and other family circumstances.  The key aims of the universal credit are to provide a basic income for people out of work, make work pay as people move into and progress in work and help lift people out of poverty.

An item of observation that can assume various values, for example, square feet, sales prices, or sales ratios. Variables are commonly described using measures of central tendency and Dispersion.

A measure of spread about the mean, the square of the Standard Deviation.

The weighted-average gross interest rates of the pool of mortgages that underlie a mortgage-backed security (MBS) at the time the securities were issued. A mortgage-backed security's current WAC can differ from its original WAC as the underlying mortgages pay down at different speeds. In the weighted-average calculation, the principal balance of each underlying mortgage is used as the weighting factor.

The average number of years for which each dollar of unpaid principal on a loan or mortgage remains outstanding. Once calculated, WAL tells how many years it will take to pay half of the outstanding principal.

The weighted average of the time until all maturities on mortgages in a mortgage-backed security (MBS) are repaid. The higher the weighted average to maturity, the longer the mortgages in the security have until maturity. Also known as "average effective maturity".

A term used to distinguish between an original mortgage loan and a pass-through security.