Architectural, Engineering and Related Services Price Index (AESPI)
Detailed information for second quarter 2017
The purpose of the Architectural, Engineering and Related Services Price Index (AESPI) is to measure changes in prices over time for the services of these industries. Prices for representative contracts of the services of architects, landscape architects, engineers, geophysical and non-geophysical surveyors are measured on a quarterly basis.
Data release - September 22, 2017
The Architectural, Engineering and Related Service Price Index (AESPI) is a longitudinal survey that collects information on the prices of architectural, engineering and surveying and mapping services, on a quarterly basis. Architectural services are divided into two categories - Architecture and Landscape architecture. Surveying and mapping services are delineated in geophysical and non- geophysical categories.
The AESPI is a useful indicator of economic activity in the architectural, engineering and related services industry (NAICS 5413). These indexes can also prove helpful as a supplementary tool for performance evaluation, cost monitoring contract assessment and benchmark comparisons. In addition, the indexes are used by the Canadian System of Macroeconomic Accounts to arrive at estimates of constant-dollar value-added. Constant-dollar value-added is needed to measure productivity changes in the industry.
In order to follow the price of a constant-quality service over time, this survey adopts the model-pricing approach. The model is intended to capture realistic details or the price components (cost of direct labour, overhead, profit and other applicable direct costs) of a typical project. The model is intended to remain static over time, however, the AESPI methodology allows for the model to be updated in order to maintain its representativeness. The model is a representative contract that is selected by the survey respondent during the initialization phase of collections.
This index is part of the Services Producer Price Index program (SPPI) at Statistics Canada.
The SPPI program develops and produces price indexes for a number of business service categories. This initiative fills an important data gap in the area of economic statistics and has resulted in a more comprehensive set of service price indexes. These indexes allow Statistics Canada to produce more accurate estimates of real-value added (Gross Domestic Product) and changes in productivity.
Reference period: The time period for which the AESPI equals 100; currently this is the year 2013.
Collection period: Data collection occurs during an eight week period starting on the 15th (or next business day) of the second month of the quarter.
- Business, consumer and property services
- Prices and price indexes
- Professional, scientific and technical services
- Service price indexes
Data sources and methodology
The target population for the AESPI is establishments belonging to one of the five NAICS industries listed below. All of these 6-digit industries are part of NAICS 5413 - Architectural, Engineering and Related Services.
¿ 541310 Architectural Services
¿ 541320 Landscape Architectural Services
¿ 541330 Engineering Services
¿ 541360 Geophysical Surveying and Mapping Services
¿ 541370 Surveying and Mapping Services (except Geophysical)
The observed population for the AESPI differs from the target population due to the exclusion of the smallest (by revenue) establishments in the five in-scope NAICS industries. Within this subset of NAICS 5413, businesses comprising the bottom 10-percentile of the revenue of their industries are excluded from the survey. This exclusion is done in an effort to reduce response burden on smaller firms.
The AESPI uses an electronic questionnaire (EQ) to survey the target population. The electronic questionnaire was developed in 2015 and was based on the paper version of the questionnaire that had been used from 2012 through the second quarter of 2015. The original paper version of the AESPI was designed in consultation with the target industries as well as statistical methodologists within Statistics Canada. The EQ was field tested with survey participants in the spring of 2015. The Questionnaire Design Resource Center facilitated the questionnaire testing, and Statistics Canada representatives visited survey participants in Montreal, Toronto and Calgary.
The AESPI electronic questionnaire is based on the model pricing approach. Under the model pricing approach, survey participants re-price a model contract that is representative of the typical work in which the firm engages. During the initialization phase of collection, survey participant select and specify a contract that they have completed in the past two years. The model should remain static over time so long as it remains representative of the typical work in which the firm engages. In the event that the selected contract becomes obsolete, the firm may specify a new contract as its model. By holding the characteristics of the model contract constant, this approach allows a constant-quality service price to be calculated. This constant quality price then feeds in to the Canadian System of Macroeconomic Account's (CSMA) estimates of constant dollar GDP.
This is a sample survey with a cross-sectional design and a longitudinal follow-up.
The active sample for the AESPI is approximately 600 units. The current sample was drawn from those establishments comprising the observed population as of April 2014. The probability of an establishment being selected into sample is proportional to its revenue.
Responding to this survey is mandatory.
Data are collected directly from survey respondents.
Following sample selection, new survey participants (respondents) are introduced to the survey through telephone calls. During this initial phase of data collection, respondents are guided through the process of selecting representative products for which prices will be monitored. This process typically spans several collection cycles until respondents become conversant with the survey.
In subsequent cycles, monthly data are collected on a quarterly basis via electronic questionnaire and by mail out, mail back paper questionnaires, while telephone communication (Computer Assisted Telephone Interviewing) is used for non-response and data follow-up. Several follow-up contacts can be made including sending out a reminder fax or letter in order to collect data.
The instrument through which the data for the AESPI are collected is through the Architectural, Engineering and Related Services Price Report (AERSPR). This instrument is an Electronic Questionnaire (EQ) that is available in both English and French. This EQ serves as both the means of collection and capture for the AESPI.
Built into the AERSPR are several edits that if tripped, will automatically trigger a follow up from the collections team at the regional office (RO). The edits have been designed to catch potential entry errors from the survey respondent. In the event that an edit is tripped, the RO will contact the respondent to verify that the data that has been received is correct and was not the result of a keying (or other) error.
Information about the time it takes respondents to complete the survey questionnaire is collected and monitored closely. Currently, it takes respondents an average of 20 minutes to complete the survey.
View the Questionnaire(s) and reporting guide(s) .
Error detection is conducted at the time of data collection and also during post collection processing, using a set of systematized error detection procedures to identify outliers and possible reporting anomalies. Records that fail these edits are reviewed for editing and correction when necessary or edit failure may trigger a follow-up with the respondent.
Time and effort is devoted to keeping the specifications constant such that only the pure changes in price are tracked. Some information are also collected in order to ensure, as much as possible, that the collected data correspond to the same specifications over time. This constant quality price then feeds into the Canadian System of Macroeconomic Accounts' (CSMA) estimates of constant dollar GDP.
Missing data are generally estimated by a systematized imputation process. In any given period, price data may not be available for estimation. In such cases, missing data are imputed using the average price movement of remaining units within the same stratum (overall mean or targeted mean imputation method).
The Architectural, Engineering, Surveying and Mapping Services Price Index (AESPI) is a compilation of price quotes for model (representative) contracts that are collected directly from survey respondents.
The AESPI is aggregated using revenue weights for each establishment. Estimates are produced by calculating a weighted average of the price relatives, by industry. The AESPI has three sub-components - architecture and landscape architecture services, engineering services, and surveying and mapping services. These three sub-components are weighted together using revenue weights relative to each sub-components' share in NAICS 5413 in order to arrive at the AESPI.
Estimates are produced by calculating a weighted average of price relatives by industry, which are chained together to form an index series.
The AESPI is a Laspeyres chain linked index, available at the Canada level only.
An in-depth assessment of quality is conducted prior to the dissemination of estimates. This assessment is based on two key elements of quality (accuracy and coherence); as defined in Statistics Canada's guidelines for the validation of statistical outputs.
The survey's data collection strategy is designed to ensure that targeted response rates are met every cycle. Analysts pay close attention to this metric and react appropriately to ensure that the survey's coverage of the industry is thorough. Particular attention is also given to ensuring that sampled products or services are representative of actual transactions happening in the market place. These two activities, fundamental to the overall quality of the estimates, are done consistently.
Analysts also undertake additional validation activities every cycle to ensure the coherence of survey estimates. These include among others activities: analysis of price changes over time (including analysis of trends), at the business/company, industry, subsector and sector levels; certification of key contributors to price change; and confrontation of estimates against other related data sources. Contextual analysis of survey results is also performed in light of prevailing economic conditions.
Engagements with relevant stakeholders are also undertaken periodically. Forums involving other Statistics Canada analysts, industry stakeholders and partners at other national and international statistical agencies provide valuable insights that inform the development and research agenda of the program.
Statistics Canada is prohibited by law from releasing any information it collects which could identify any person, business, or organization, unless consent has been given by the respondent or as permitted by the Statistics Act. Various transformations are applied to collected price data in the calculation of price indexes, such that it is not possible to identify the raw price data obtained from any survey participant. Confidentiality rules are also applied to price indexes that are released or published to prevent the publication or disclosure of any information deemed confidential. If necessary, data are suppressed to prevent direct or residual disclosure of identifiable data.
Revisions and seasonal adjustment
The data are not seasonally adjusted. There will be one revision period, plus an annual revision released with second quarter data of the following reference year.
With each release of data, the previous quarter's data is subject to revision. These revisions occur when late data is collected for a previously non-responding establishment. Data that was excluded from the previous quarter's estimation as unsuitable can be re-integrated once it has been confirmed or corrected with the respondent.
The statistical accuracy of this index depends on price and weight data obtained from sample surveys. Each type of input data is subject to its own errors. Processing procedures for editing and imputation are in place to ensure the quality of data. Consequently, the aggregate indexes at all levels are considered to be statistically reliable.
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