Methodology Introduction.
First: Scope.
Second: Design.
Third: Organization.
Fourth: Data Collection.
Fifth: Disaggregation
Sixth: Review.
Seventh: Publication.
Eighth: Assessment.
Ninth: Management
Introduction:
The General Authority for Statistics (GaStat) applies in all its statistical work a unified methodology that conforms with the nature of each statistical product. It depends on the Handbook of Statistical Work Procedures, which is compatible with internationally approved procedures. Statistical products go through eight major stages, in addition to a ninth stage represented in the comprehensive “management” stage which is illustrated in the following figure and the subsequent explanations:
The first three stages (scope, design and organization) are collaborative stages between GaStat and its clients who are data users from development entities. The fourth stage (data collection) is a collaborative stage between GaStat and the statistical population, whether they are households or establishments, to complete data and information. The remaining stages (classification, reviewing and publication) are statistical and are undertaken by GaStat. Afterwards, the eighth stage (assessment) is also done in collaboration with the clients. The management stage is administrative and organizational and spans all other stages. Those stages have been applied in the Consumer Price Index (CPI) as follows:
It is the starting point for producing the (Consumer Price Index). It is also the first collaborative stage between relevant GaStat departments like the Price Statistics Department, as the department responsible for preparing the results of the consumer price index, and the Living Conditions Department as the department provided with the Household Income and Expenditure Survey 2018, in addition to the National Accounts Statistics Department as the beneficiary of results of the consumer price index. Workshops and meetings were held
to discuss these results and identify the consumption patterns of households. The views of those departments regarding all the items included in the CPI basket preparation, are taken into consideration to ensure the attainment of all CPI objectives, which are summed up as follows:
- To provide data on retail prices for goods and services included in the consumer basket.
- To provide a time series of statistical data on consumer price indices.
This stage also involves ensuring that the published statistics will contribute to meeting the requirements of Saudi Vision 2030 as well as covering regional requirements, such as the GCC Statistical Center, and international requirements represented in the International Monetary Fund.
This stage is for designing statistical work as an integrated product. It also includes identifying the statistical population, designing the statistical framework and the survey sample along with its questionnaire, identifying the method and tools of data collection and identifying the sampling units.
The most important outputs of this stage are:
1. The Statistical Population
The statistical population in the consumer price index bulletin consists of all points of sale engaged in retail activity (sale of goods, delivery of services) and leased housing units in the Kingdom.
2. Statistical Sources
The consumer price index depends for its data on a field survey conducted by GaStat on a monthly basis, and is listed under the classification of (economic statistics). The survey involves collecting prices by visiting a prespecified sample of points of sale engaged in retail activity (sale of goods, delivery of services), as well as housing units in various administrative areas in Saudi Arabia. Afterwards, an electronic questionnaire that includes a number of questions regarding goods, services and housing units is completed, and estimations and indicators are provided in relation to the consumer price index.
3. Setting the Base Year
The year 2018 was set as a base year as it meets the required conditions in terms of economic and social stability and witnessed no crises. It is also the year the Household Expenditure and Income Survey was conducted.
4. Terminology and Concepts of the Consumer Price Index
4.1. Index Number: Index number is a rational number that measures variation in one or more phenomena. It is calculated by dividing its face value at the comparison period by its value at the base period.
4.2. Consumer Price Index: A statistical metric that measures changes in the prices of a stable market basket of goods and services.
4.3. Goods and Services Basket: The actual group of goods and services that household consumers spend on for living purposes.
4.4. Household Expenditure and Income Survey: The expenditure and income survey reflects the spending patterns of Saudi households on goods and services. The results of expenditure and income survey are also used to determine the relative distribution of expenditure on goods and services in order to use them in the production of the consumer price index.
4.5. Household Expenditure: Household expenditure can be defined as how much all household members spend to get (consumer and non consumer) goods and services during a reference period. This includes what is spent on the household directly such as: food, housing, electricity, durable goods…etc, or what is spent on individual members such as clothes and personal items, etc.
4.6. Relative Importance of Goods and Services: The percentage of expenditure on certain goods or services compared to the total expenditure on goods and services inside the consumer basket.
4.7. Points of Sale: Establishments and units from which the prices of goods and services that are included in the goods and services basket, are collected. For example, retail shops such as grocery stores, clothing shops, and other kinds of shops like the ones that provide doctors' services, as well as rental units (apartment, villa, a floor of a villa, old house), and other services shops.
4.8. Shadow Sample: It is a set of backup points of sale which can be referred to when needed to replace one of the main points of sale when it becomes difficult to get the price from that point for any reason, whether because the shop is closed permanently or because certain goods are no longer available.
4.9. Comparison Period Price: It is the recorded price of a commodity or a service in the current period of time.
4.10. Base Period Price: It is the recorded price of a commodity or a service in a previous period of time with which the current price is compared.
5. Calculation Equations:
| Calculation Equation | |
| Monthly change (Laspeyres formula) |
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| Cumulative index | = Previous index × monthly change |
| Relative importance |  |
6. Adopted Statistical Classification
Classification is defined as being an arranged set of related categories used for data collection according to similarity. It is the basis for collecting and publishing data in all statistical fields, such as economic activity, products, expenditures, jobs or health, etc. It allows for classifying data and information through putting them into meaningful categories to produce useful statistics, considering that data collection requires precise and methodological arrangement in accordance with their common features so that the statistics can be reliable and comparable. The consumer price index is subject to the following classification: (COICOP) Classification of Individual Consumption by Purpose.
7. Relative Importance and Identification of Goods and Services
Classification is defined as being an arranged set of related categories used for data collection according to similarity. It is the basis for collecting and publishing data in all statistical fields, such as economic activity, products, expenditures, jobs or health, etc. It allows for classifying data and information through putting them into meaningful categories to produce useful statistics, considering that data collection requires precise and methodological arrangement in accordance with their common features so that the statistics can be reliable and comparable. The consumer price index is subject to the following classification: (COICOP) Classification of Individual Consumption by Purpose.
The following table shows the relative importance (weights) for each division:
| Expenditure groups (2018) | COICOP Code | Relative importance % |
| General Index | 0 | 100.00 |
| Food and Beverages | 01 | 18.78 |
| Tobacco | 02 | 0.60 |
| Clothing and Footwear | 03 | 4.20 |
| Housing, Water, Electricity, Gas, and Other fuels | 04 | 25.50 |
| Household Furnishings and Equipment | 05 | 6.74 |
| Health | 06 | 1.43 |
| Transportation | 07 | 13.05 |
| Communication | 08 | 5.62 |
| Recreation and Culture | 09 | 3.06 |
| Education | 10 | 2.87 |
| Restaurants and Hotels | 11 | 5.60 |
| Miscellaneous Goods and Services | 12 | 12.57 |
- Selection of the basket of items (goods and services) according to the results of the Household Expenditure and Income Survey 2018:
After calculating the relative importance of the total list of items, the content of the consumer price index basket is determined. Each item weighing or exceeding 0.2% is within the consumer price index basket, Meanwhile each item weighing less than 0.02%, its weight is distributed on other items within the same class in a proportional way. This percentage was chosen as an acceptable percentage in terms of coverage of most of the goods received from the Household Expenditure and Income Survey. Most countries use this ratio; thus, we obtained a basket of items containing 490 items.
8. Design of Survey Questionnaire:
The two questionnaires used for collecting field data were prepared and designed by price statistics specialists at GaStat as follows:
Questionnaire for collecting data on goods and services from points of sale: The questionnaire includes auxiliary geographic data to arrive at the points of sale. It also includes a description of the commodity or service whose price, specifications and unforeseen changes need to be monitored, in addition to price factors.
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The complete questionnaire can be viewed and downloaded via GaStat’s official website |
8.2 Questionnaire for collecting data on leased housing units: The questionnaire includes auxiliary geographic data to arrive at the leased housing unit. It also includes a description of the unit type, pricing cycle, and any distinctive features of the housing unit.
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The complete questionnaire can be viewed and downloaded via GaStat’s official website |
After being approved, the survey questionnaire will be transformed into an electronic questionnaire that can be handled through the advanced data collection system using tablet devices. The system has the following features:
- Reviewing the work zone of the field researcher.
- Reaching the sample (point of sale or housing unit) using the map on the tablet device.
- Completing data of high quality using data check rules and navigation (to automatically detect input errors and illogical inputs while the completion of the data is underway).
- Establishing communication between supervising entities by exchanging notes with field researchers.
9. Coverage:
The Consumer Price Index Bulletin covers data related to the consumer price index for all (13) administrative regions of the Kingdom of Saudi Arabia including the following cities: (Riyadh, Makkah, Jeddah, Taif, Madinah, Qassim, Dammam, al-Hofuf, Abha, Tabuk, Hail, Arar, Jazan, Najran, al-Baha, al-jouf), by collecting pricing data through field visits to prespecified points of sale and housing units.
Most basket item prices are collected monthly, at a rate that exceeds (80%) of the total number of items. The collected data is classified based on the calendar month in which price data is collected. The pricing period lasts (4) weeks per month, which guarantees full temporal coverage throughout the month, and ensures commitment to a specific pricing cycle for each item (weekly, monthly, quarterly, and semi-annual).
10. Statistical Framework:
An appropriate framework was set up for retail and leased establishments including a number of technical controls that govern this process. The most important technical controls used were the following:
- Carrying out the points of sale survey, which aims to: identify and enumerate establishments that engage in retail activity; determine the items that are available at the establishment from the list of pre-defined items required to be priced (items included in constructing the CPI basket); create a general framework for selecting a sample from those establishments and housing units to collect item prices; as well as determine shadow samples that can be used as a substitute for the basic sample in the event that one of these points of sale is no longer available for some reason.
- Using of the results of the Census of Establishments to ensure that the distribution at the level of neighborhoods within the pricing cities by economic activity is carried out according to the (ISIC4) classification at the level of (2,4, and 6) limits, especially with consideration to retail and wholesale establishments and services.
- Benefiting from the framework of the current Census of Population and Housing in determining the leased housing units.
- Utilization of city maps and distributions of neighborhoods, sectors and blocks.
- Benefiting from the current framework of establishments and leased housing units used in the survey of the consumer price index.
- Taking into account the shopping scale changes of different types of sources of sale and purchase according to the sub-groups that were obtained in the final results of the Household Expenditure and Income Survey.
11. Sample design:
Points of sale from which the prices of different goods and services are collected were selected based on:
- Population size of the geographical area.
- Specialty point of sale.
- Percentage of the number of shops available in the general framework of the census of establishments at the city level.
- Market type.
- Shopping percentage based on the Household Expenditure and Income Survey results at the city level.
- Shopping ratios linked to the type of point of sale.
- Percentage distribution of points of sale by commercial activity.
- The volume of employment at the point of sale.
A shadow sample is then selected to be used as a substitute if the original point of sale is not available.
It includes the following data:
- Names and addresses of retail and service establishments.
- List of goods and services provided by those establishments.
- Longitude and latitude coordinates of the establishments for quick access and subsequent application of the quality control program to ensure accuracy of the data.
Description of the point of sale activity and whether it is specialized or not specialized.
It is the final preparation stage and precedes the visits to establishments (points of sale or leased housing units) and data collection. In this stage, the required workflow procedures are established for preparing the consumer price index, starting with the collection stage and ending with the assessment stage and the organization and grouping of those procedures. The optimal sequence of those procedures is chosen to arrive at a methodology that achieves the objectives of the consumer price index. A review was made in this stage of the procedures that were taken upon the preparation of the previous version of the consumer price index to develop the work procedures in the current version. Those procedures were also described and documented to facilitate any updates in future rounds. The statistical workflow procedures were tested and examined to ensure their compliance with the requirements of preparing the consumer price index in its final form, approve the procedures of the statistical workflow, and develop a roadmap for implementation.
Testing the efficiency of input systems and the process of transmitting, synchronizing and reviewing data through either the tablet or office system of the consumer price index are the main procedures in this stage.
First: The survey sample is selected as defined in the step set for “designing and drawing the sample”. The sample in each of the survey cities was divided according to the population as follows:
| Population | Cities | Number Point of sale per item |
| More than (1) million people | Riyadh – Makkah – Jeddah – Dammam | 10 POS |
| More than 400 thousand and less than one million people | Madinah – Taif – Hofuf – Abha – Buraydah –Tabuk | 7 POS |
| Less than 400 thousand people | Hail – Jazan – Najran – Al-Baha – Sakaka – Arar | 5 POS |
Second: The workers, who were nominated as field researchers and visited the establishments (points of sale/ leased housing units) to collect the consumer price index data, were chosen on the basis of several practical and subjective criteria related to the nature of work, such as:
- Educational level.
- Fieldwork experience.
- Personal attributes, such as: good conduct, good senses and physical and psychological fitness.
- The candidate’s success in the training program of the consumer price index.
- The candidate must not be under the age of 20.
Third: All candidates (GaStat staff and collaborators from some government entities) are qualified and trained through special training programs in two phases as follows:
- Phase 1: (qualification and training of researchers responsible for identifying and updating points of sale).
- Phase 2: (qualification and training of researchers responsible for the process of collecting prices).
The training process is carried out in two phases as follows:
- A training program was held for competent staff members in GaStat’s headquarters for one week.
- Similar training programs were held for collaborating researchers from all survey cities.
| The training programs offered to field researchers tasked with collecting the Consumer Price Index data include: Practical and hands-on lectures on technical, technological, administrative, and awareness materials that are used in data collection processes. Field researchers are also introduced to the survey’s objectives, the data collection method, and how to use maps and reach the holdings. The training programs also include a detailed explanation of all the parts on the questionnaire, as well as any technical and administrative tasks. Field researchers are also trained on how to deal with the public and how to ask the questions in record time. |
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At the beginning of the training program, all trainees are provided with tablet devices that enable them to do the following:
Staff members are nominated to participate in the data collection process according to the results of their assessment at the end of the training program. |
Fourth: The method of direct contact with the establishments (points of sale or leased housing units) was adopted in the process of completing the survey questionnaire and data collection. Field researchers visit the points of sale or housing units by using the coordinates recorded on the tablets and the guiding maps. Afterwards, they introduce themselves, showing official documents proving their statistical identity. They will also clarify the aim of their visit, present an overview of the survey and its objectives and complete the electronic questionnaire through verbal discussion with the managers of the point of sale or the tenant of the housing unit.
Fifth: All field researchers use tablet devices to complete the survey questionnaire data.
Sixth: Field researchers at all work locations in the Kingdom use the “synchronization” feature available on tablet devices to download and transfer the completed data of the points of sale or leased housing units directly to the database linked to them at GaStat’s headquarters where they are stored in a specific way to be reviewed and processed at a later stage.
Seventh: Check rules are applied electronically to guarantee the consistency, precision and rationality of the data of the consumer price index questionnaire. They are electronic rules that identify contradictions between answers and they were designed by using a logical link between the answers of the questionnaire and its variables to help field researchers directly identify any errors upon completing the survey data with the official in charge of at the establishment or the tenant of the housing unit. Those programmed rules don’t allow any mistakes to go through when an answer contradicts with another piece of information or another answer in the questionnaire.
Eighth: The collected data is verified and reviewed by the field researcher, their inspector and the survey supervisor in the supervision area. All work areas are subjected to a monitoring and reviewing process from the Price Statistics Department at GaStat’s headquarters. The department also controls and monitors the performance of all working groups in the field during the data collection process, from the first day and until the last day.
Fifth Stage: Disaggregation of Data:
The processes of disaggregating the raw data of the consumer price index use inputs of classification and coding formed during the data collection process, whether the adopted statistical classification is the one being referred to in the design stage, i.e. the Classification of Individual Consumption by Purpose (COICOP) or any other classification like the geographic data classification (for instance data distribution at the level of administrative regions and cities). Data are displayed in suitable tables so that they can be easily summed up, understood and comprehended to obtain results, make comparisons and extract statistical implications about the study population. It will also be easier to refer to them as tables without the need to read the original questionnaires which often include some data, such as the addresses of establishments or leased housing units in violation of the principle of statistical data confidentiality.
Data is processed at this stage through taking a number of steps, mainly:
First: Verifying data comprehensiveness and consistency
Data are reviewed in terms of their comprehensiveness andconsistency and matched to ensure their accuracy and precision in a way that suits their nature. The data of the current round (current month) are matched with the data of the previous round (previous month) to verify them as a prelude to processing data and extracting and reviewing results in the stages that follow the disaggregation stage.
Second: Data anonymization
To ensure data confidentiality, identifiers are removed from a set of input data, such as hiding the names of individuals, points of sale, addresses and other identifiers to ensure the protection of people’s privacy.
First: Verifying data outputs
After reviewing and verifying the data collected for preparing the consumer price index, GaStat calculates and extracts results, and uploads and stores outputs in the database. Afterwards, final reviewing processes are conducted by specialists in price statistics using modern technologies and software designed for the purposes of reviewing and checking.
Second: Handling of confidential data
Pursuant to Royal Decree No.23 dated 07/12/1397, GaStat is committed to the absolute confidentiality of all completed data and not using them except for statistical purposes. Therefore, data are safely stored on GaStat’s servers.
| No individual data shall be disclosed in any way. Materials set for publication are only aggregated statistical tables at the level of the Kingdom, the administrative regions and the major cities based on their features. |
First: Preparing the results set for publishing
In this stage, GaStat uploaded the data results from the consumer price index database. Afterwards, GaStat prepared publication tables and graphs for both data and indicators, and added descriptive and methodological information to them. These were prepared in both Arabic and English.
Second: Preparing media material and announcing the bulletin’s release date
After announcing the bulletin’s release date on its official website at the beginning of the calendar year, GaStat prepares the required media materials to announce the bulletin’s release on all media outlets, as well as its various social media platforms. The announcement will be made on the date set for publication. The bulletin will be published on the official website in various templates of open data in Excel format which will be available on the website’s statistics library. This guarantees its circulation and access to all clients and parties interested in the consumer price index.
Third: Communicating with clients and providing them with the bulletin
GaStat pays great importance to communicating with clients who use its data. Therefore, GaStat contacts clients upon the release of the consumer price index bulletin to provide them with it. GaStat also receives questions and enquiries from clients regarding the bulletin and its results through various communication channels. Clients can contact GaStat to request data. Questions and inquiries are received via:
- GaStat’s official website: www.stats.gov.sa
- GaStat’s official email: info@stats.gov.sa
- Client support email: cs@stats.gov.sa
- Visiting GaStat’s headquarters in Riyadh or one of its branches in the regions of the Kingdom.
- Official Letters..
- By Statistical Phone (920020081)
Fourth: Published Content Preservation
GaStat’s Documents and Archives Center stored and archived the data of this bulletin to refer to it at any time upon request. GaStat took that step out of its awareness of the importance of electronically preserving this data to easily refer to it when needed.
After the bulletin is released and received by all GaStat’s clients, the clients are contacted again in this stage which allows for assessing the whole statistical process that was carried out, with the aim of constant improvement to obtain high-quality data. The improvements may include methodologies, processes, systems, statistical researchers’ skill and statistical frameworks. This stage is done in collaboration with data users and GaStat’s clients through a number of steps:
First: Collecting measurable assessment inputs
Main comments and remarks are collected and documented from their sources at all stages, including those collected and documented during the collection stage, such as: comments and remarks presented by data collectors and their field supervisors, in addition to data collected and documented during the assessment stage such as the remarks deduced by specialists concerned with reviewing, checking and analyzing data collected from the field. Finally, comments and remarks presented by data users are collected and documented after publication, in addition to what is being monitored via media outlets or the clients’ remarks which GaStat receives through its main channels.
Second: Making the assessment
Collected assessment inputs are analyzed, and on that basis a number of improvements and possible solutions are identified and discussed with relevant parties in all concerned GaStat departments or its clients who are partners in the consumer price index bulletin. This step also involves performance measurement of the clients’ use of the results of the consumer price index bulletin and their satisfaction with them, contacting unsatisfied clients and providing them with clarifications.
On the basis of those procedures, an agreement will be made on the suggested recommendations to obtain high-quality data in the following round of the consumer price index bulletin.
A comprehensive stage that spans over all the stages of producing the consumer price index. This stage determines the general production plan, including the feasibility study, risk management, means of funding, disbursement mechanisms, as well as developing performance indicators, quality parameters, human resources map necessary for production, following up on the execution of tasks assigned to all departments in every stage, and making reports to ensure that the GaStat fulfills its commitments towards its clients.
