Methodology and Quality Update

Latest Update on Methodology and Quality

15/09/2025

Statistical Presentation

Data description
•   Consumer Price Index (CPI)
It is an economic indicator that reflects relative changes in the prices of a fixed basket of goods and services that represent consumer spending patterns in Saudi Arabia over a specific period of time compared to the reference period. This index is considered a key tool for measuring inflation or deflation rates, and it is widely used in economic and statistical reports and analyses. The index is based on data collected through precise field surveys, in addition to administrative records, and is characterized by a number of features that ensure its accuracy and reliability as an indicator reflecting price movements in the local market, including:  

•    Monitoring retail price movements of goods and services within the consumer basket.
•    Providing a time series of statistical data on price indices.
•    Classifying statistics by consumption categories, including price indices and monthly and annual rates of change.
Through the Consumer Price Index (CPI), a number of objectives can be achieved, including:
•    Measuring inflation or deflation.
•    Providing data that support the formulation of economic and social policies by monitoring inflation rates and supplying accurate data for decision-makers.
•    Meeting regional and international requirements, such as those of the GCC-Stat and the International Monetary Fund (IMF).
Concepts and definitions of the Consumer Price Index (CPI):
The price data collected from the survey are used to estimate a wide range of indicators, including:
Indices by expenditure categories (detailed), including:
•     Indices and rates of change by expenditure category (for the reference month).
Indices by region and expenditure categories, including:
•    Indices by region and expenditure category (for the reference month).
•    Annual rate of change by region and expenditure category (for the reference month).
•    Monthly rate of change by region and expenditure category (for the reference month).
Indices by expenditure categories, including:
•    Time series of indices by expenditure category since 2013.
•    Time series of annual rates of change by expenditure category since 2014 (%).
•    Time series of monthly rates of change by expenditure category since 2013 (%).
Indices by administrative region, including:
•    Time series of indices by administrative region since 2013.
•    Time series of annual rates of change by administrative region since 2014 (%).
•    Time series of monthly rates of change by administrative region since 2013 (%).
The annual average of the index, published at the end of each calendar year.

Classifications

Classification of Individual Consumption by Purpose (CoICOP):
It is an international reference classification issued by the United Nations, used to organize and classify household expenditure on goods and services according to their purpose. This classification aims to facilitate statistical analysis and the comparison of consumption patterns across countries and sectors, and it serves as a standard tool for harmonizing data related to individual consumption patterns. 
The classification consists of 13 main divisions and includes six levels of detail: Section, group, class, category, subcategory, and item, mainly used in constructing the consumer price index to classify the components of the consumption basket according to their purpose of use.
Source: United Nations  https://unstats.un.org/unsd/classifications/coicop

Statistical concepts and definitions

Concepts and definitions of the Consumer Price Index (CPI):
•    Index number:
An index number is a relative figure that measures the change in one or more phenomena. It is calculated as the ratio of the value of the phenomenon in the comparison period to its value in the base period.
•    Consumer Price Index (CPI):
The Consumer Price Index (CPI) is defined as a statistical measure of the price movements of a fixed basket of goods and services that represent consumption expenditure patterns, during a specific period of time compared to the reference period. 
•    Basket of goods and services:
A set of goods and services on which the household consumer spends for living purposes. 

•    Household Income and Expenditure Survey:
The Household Income and Expenditure Survey is one of the sample household field surveys. It provides data on income and expenditure patterns in society, reflecting household spending on goods and services in the Kingdom, as well as household income levels. The results of the Household Income and Expenditure Survey are used to determine the relative distribution of expenditure on goods and services that make up the household expenditure index:   It is the value of what all household members spend during the reference period in return for obtaining goods and services (both consumable and non-consumable), whether this expenditure relates to the household such as: …expenditure on food and beverages, housing, electricity, acquisition of goods, or access to services, as well as expenditure related to household members, such as spending on clothing, personal items, and the like.

•     Relative importance of an item:
Percentage of expenditure on a specific good or service from the total expenditure on all goods and services within the consumer basket.
•    Points of sale:
Establishments or units from which price data are collected for the goods and services included in the consumer basket, such as retail outlets (e.g., grocery stores, food shops, and clothing stores), in addition to service providers for consumers, such as clinics, doctors’ services, and other service outlets.
•    Shadow sample:
It is a set of backup points of sale that can be referred to when needed to replace one of the basic 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 the commodity is definitely unavailable.
•    Comparison Period Price:
It is the recorded price of a commodity or a service in the current period of time.

•    Reference 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.

•    The index for basic materials:
It is the general index after excluding items with price volatility, namely food and beverages, and energy items.

•    Consumer goods index:
It is a statistical measure that reflects changes in the prices of goods consumed by individuals, and it includes: durable goods, semi-durable goods, and non-durable goods.

•    Durable goods: 
Goods that are used over a relatively long period (usually more than three years) and are not consumed upon first use, such as: furniture, cars, and electrical appliances.

•    Semi-durable goods: 
Goods that last for a medium period (about one to three years) and gradually lose their value with use, such as: clothing, footwear, and simple household items.

•    Non-durable goods:
Goods that are consumed quickly or within a short period (less than one year) and are often not reusable, such as: food, beverages, fuel, and medicines. 

•    Services index: 
It is a statistical measure that reflects changes in the prices of goods consumed by individuals, and it includes: transport, education, healthcare, and communication services.

•    Chain-linked series: 
It is a statistical methodology used in calculating the consumer price index. It relies on annually updating the weights of the basket of goods and services based on the results of final household consumption expenditure derived from the national accounts, instead of depending on a fixed base year in which constant weights are used for several years, usually based on the results of the household income and expenditure survey conducted every three to five years. The index results are linked at the beginning of each calendar year with the new weights, allowing the construction of a flexible and consistent time series that more accurately reflects changes in consumption patterns and price fluctuations, thereby enhancing the accuracy and flexibility of the index in representing consumer behavior. 
Advantages of the chain-linked methodology:

•    Higher accuracy in representing consumption patterns: It reflects the actual annual changes in consumer behavior, thereby enhancing the realism of the index.
•    Flexibility in keeping pace with economic transformations: It adapts to rapid market changes, such as price fluctuations or the emergence of new products.
•    Use of a dynamic reference year: For example, 2023, which is used to link the years in a consistent manner without the need to fully reconstruct the time series.
•    More reliable international comparisons: It is consistent with the methodologies adopted in most G20 countries, which facilitates conducting accurate economic comparisons.

Data sources

The data of the consumer price index statistics rely on two main sources:
First source: Field surveys, which constitute the primary source of consumer price index statistics. They include field visits to the survey sample in 23 cities representing the thirteen administrative regions of the Kingdom.
The main published variables of Producer Price Survey data are:
•    Consumer price indices by regions and expenditure categories.
•    Annual change rates in consumer price indices.
•    Monthly change rates in consumer price indices.
Second source: Administrative records for consumer price index statistics :
Such as: Data extracted from administrative records, from the “Ejar” platform, which include:
•    Rental value of villas, apartments, and floors.
The main published variables from the administrative data source are:
•    Consumer price indices for rental items by the Kingdom, regions, and expenditure categories.
•    Annual change rates in consumer price indices for rental items.
•    Monthly change rates in consumer price indices for rental items.

Designing the data collection tool

The consumer price survey questionnaire has been designed to be an effective and comprehensive tool for collecting the required data with accuracy and methodology. The questionnaire consists of two main parts:
Identification data:
This data include basic information that helps accurately identify the point of sale and the geographical location, and they comprise:
•    The establishment’s number and type (such as retail store, supermarket, pharmacy, etc.)
•    Name of the establishment (point of sale).
•    Detailed address and geographical location (including city, neighborhood, and postal code).
•    Contact information (such as phone number).
Items and prices data:
This part contains a list of goods and services included in the consumer basket, and detailed data are collected for each item in accordance with the approved standard specifications. These include:
•    Item name (good or service).
•    Quantity or standard unit of measurement (such as kilogram, liter, unit, etc.).
•    Country of origin of the product.
•    Current and previous price of the item.
•    Availability status of the item at the point of sale.
Notes related to any price changes, such as promotional offers or changes in quality or size.
Special codes to explain price changes (such as an increase due to a change of supplier, or a decrease due to a seasonal discount, etc)
This questionnaire is designed in a way that facilitates field researchers’ accurate and reliable data entry. It also allows for reviewing and verifying price changes, thereby ensuring the production of high-quality statistical data that accurately reflects price realities in the local market.

Questionnaire test (cognitive test)

Not applicable.

Statistical population

The statistical population of the consumer price index consists of all goods and services included in the consumer basket, whose prices are obtained from retail outlets and service providers in the Kingdom of Saudi Arabia.

Sample Design

A dual approach has been adopted for the sample design, consisting of two main stages.
•    First: Purposive sample (first stage):
In this stage, the cities were selected based on predetermined criteria, to represent the different regions of the Kingdom, and these include:
•    Number of populations: A total of 23 cities were selected to represent the thirteen administrative regions of the Kingdom.
•    Economic activity: The availability of goods and services in the city was taken into consideration.
•    Geographical distribution: To ensure a balanced representation of the different administrative regions.
This selection guarantees diversity in consumption patterns and market prices and reflects the economic and social reality of the Kingdom.
•    Second: Stratified sample (second stage):
After determining the cities, the stratified sampling method was applied using an updated frame of points of sale, through multiple stages.
•    Phase one: Dividing the cities into strata based on geographical regions.
•    Phase two: Selecting clusters (such as residential neighborhoods or commercial complexes) randomly from each stratum.
•    Phase three: Selecting points of sale within the chosen clusters randomly, taking into account the size of each point of sale to ensure appropriate representation.
This methodology represents an integrated framework that ensures the quality and accuracy of the data and enhances the reliability of the survey results.

Statistical unit (sampling unit)

The statistical unit in the consumer price index is every good or service whose price is measured within the consumer basket.

Data collection

Data collection method from surveys:
Data for the Consumer Price Index is collected through Computer-Assisted Telephone Interviews (CAWI), Computer-Assisted Web Interviews (CAPI).
Data collection from administrative records:
In coordination with the relevant departments of the Authority responsible for survey implementation and data collection management, administrative records are obtained from the Real Estate General Authority, including data related to the rental prices of housing units rented to households. 
They will be stored in the authority's databases after auditing and reviewing according to established statistical methods and recognized quality standards, with reference to the data source in case any errors are discovered or if there are any observations regarding the data.

Data collection frequency 

The data collection process of the consumer price index survey is carried out on a monthly basis. 

Reference area

The consumer price index covers 23 cities, namely: The consumer price index covers 23 cities: Riyadh, Makkah, Jeddah, Taif, Madinah, Buraidah, Unaizah, Dammam, Khobar, Hofuf, Mubarraz, Abha, Khamis Mushait, Tabuk, Hail, Arar, Jazan, Abu Arish, Najran, Al-Baha, Baljurashi, Sakaka, and Qurayyat. These cities represent all thirteen administrative regions of the Kingdom of Saudi Arabia.

Reference period (time reference)

References period to the variables or dataset as following:
•    The collected data are attributed to the Gregorian month in which the price data are gathered, in compliance with a specific pricing cycle for each item (weekly, monthly, quarterly, or semi-annual).

Base period

The base year is updated annually using the chain-linked methodology to calculate the indices in a way that allows for the continuous updating of the weights of goods and services. Each year is linked to the previous one to form a continuous series of indices, reflecting changes in consumption expenditure patterns.
The year 2023 is the reference year on which the indices are presented, with the index value set at 100 (2023=100). It is used as a benchmark for comparison when presenting the index.

Measurement unit

The data are measured as percentages of monthly and annual changes in the indices.

Time coverage

Data are available from 2013 to the current month.

Publication frequency

The results of this index are published on a monthly basis in accordance with the approved statistical calendar, and the annual average of the consumer price index is published at the end of each Gregorian year. 

Statistical processing

Error detection

During the field price data collection process, a critical stage in ensuring data quality begins, which involves applying rules of alert, restriction, and correction, as well as reviewing the consistency and accuracy of the data compared to previous cycles. This stage aims to ensure that the data collected are reliable and free from errors or outliers before starting the statistical processing and producing the final results.
First: Implementing alert and restriction rules:
1.    Alert rules:
o    They are used to detect unusual values or those that are significantly higher or lower compared to the previous price.
o    Example: If the price of a commodity increases by 30% compared to the previous month, the system issues an alert to review this value.
2.    Restriction rules:
o    Restriction rules are applied to prevent the entry of data that are inconsistent with logical criteria or approved technical specifications.
o      Entering an analysis code that does not match the price trend, such as recording the code indicating a price decrease while the actual recorded price shows an increase.
Second: Implementing correction rules:
•    After verifying the alerts or the cases that were not allowed to be entered, correction procedures are carried out in coordination with the field teams or by referring back to the data sources.
•    Adjustments are not made automatically; rather, they undergo human review to ensure the validity of the change and to avoid affecting the credibility of the time series of the data.
Third: Comparison with previous periods
Detailed comparisons are conducted between the current cycle data and the data of:
•    The previous month to identify any unjustified monthly changes.
•    The same month of the previous year monitor annual changes and track seasonal or inflationary price trends.
•    Several previous months to analyze time patterns and detect any inconsistencies in the time series.

Data integration and matching from multiple sources 

The data are reviewed and validated to ensure their accuracy and reliability in a manner consistent with the nature of such data, with the aim of enhancing the quality and precision of the bulletin’s statistics. This includes applying alert, restriction, and correction rules after the data collection process, and comparing the data of the current bulletin cycle with those of the previous cycle to verify the integrity and consistency of the data in preparation for processing, producing, and reviewing the results. The data are also examined against previous years to identify any significant changes.

Imputation and calibration

First: In case of missing data from points of sale:
1.    Verification of the point-of-sale status:
o    Ensuring whether the outlet is temporarily or permanently closed.
o    Checking for refusal to cooperate or a temporary field obstacle.
2.    Revisiting the outlet:
o    In case of a temporary obstacle, the point of sale is revisited later within the same survey cycle.
3.    Replacement of the outlet:
o    If the outlet is permanently closed or has ceased its activity, a similar alternative point of sale is selected from the same category and geographical location.
4.    Documentation of the case:
o    Recording the note in the system, specifying the reason for the absence and the action taken (refusal, closure, relocation, etc.).
Second: In case of missing data from items (goods or services):
1.    Identifying the type of disappearance:
o    Determining whether the item is temporarily missing, seasonal, or permanently discontinued.
2.    Treatment of temporary missing items:
o    Calculating the average price from similar items or from other points of sale within the same city.
3.    Treatment of seasonal items:
o    Suspending its pricing temporarily during the period of unavailability, with the price estimated based on the price change in the higher-level category to which the item belongs.
o    Automatically resuming its pricing once it reappears in the market.
4.    Treatment of permanently discontinued items:
o    Verifying its disappearance across more than one point of sale and for more than one cycle.
o    Removing it from the sample and replacing it with an alternative item that has the same consumption characteristics.

Seasonal adjustments

1.    Treatment of seasonal items:
o    Suspending its pricing temporarily during the period in which it is unavailable.
o    Automatically resuming its pricing once it reappears in the market.
2.    Treatment of permanently discontinued items:
o    Verifying its disappearance across more than one point of sale and for more than one cycle.
o    Removing it from the sample and replacing it with an alternative item that has the same consumption characteristics.

Adjustment of preliminary results 

Not applicable, only final results will be published.

Used Resources

Quality dimensions

Suitability

A criterion that indicates how well the product meets users’ needs.

User needs 

External users benefiting from consumer price index data:
•    Government and semi-government entities.
•    Regional and international organizations.
•    Academic and research institutions, and investors.
•    Media.
•    Individuals.
Examples of key external entities benefiting from consumer price index data:
Ministry of Finance. 
Ministry of Economy and Planning.
Saudi Central Bank.

Completeness 

The consumer price index (CPI) data are based on the CPI field survey, which is a monthly survey conducted by the General Authority for Statistics under the category of Economic Statistics. In this survey, prices are collected through field visits to retail points of sale and service providers across the different administrative regions of the Kingdom of Saudi Arabia. Electronic questionnaires containing a number of goods and services are completed, through which indicators related to the consumer price index are produced. As for administrative data, they are collected from their sources at the end of each Gregorian month. 

Accuracy and reliability 

A standard that measures how close the calculations or estimates are to the exact or true values that reflect reality.

Overall accuracy 

•    The data collected is improved through the researchers, that have been selected according to a set of practical and objective criteria and training program related to the field of work.
•    Alert and validation rules are applied during the data collection process on the electronic questionnaire for the Consumer Price Index to enhance data quality.
•    Data is checked with previous years to identify any significant changes in the data.
•    The internal consistency of the data is checked before it is finalized.
•    The links between variables are checked and coherence between different data series is confirmed.

Timeliness and punctuality 

A standard that measures the time gap between the availability of information and the occurrence of the event.
However, timeliness reflects the time difference between the date of data publication and the target date when it is actually published.

Timeliness 

GASTAT uses the Special Data Dissemination Standard (SDDS) issued by the International Monetary Fund. According to this Standard, all statistics agencies are required to publish data on a monthly basis, and with a delay of no more than 6 weeks (42 days) after the end of the reference period. If the data are from different sources, they may be published in a different frequency.

Punctuality 

Publication takes place in accordance with published release dates for 
the consumer price index in GASTAT webpage.
The data are available at the expected time, as scheduled in the statistical release calendar, If the publication is delayed, reasons shall be provided.

Coherence and comparability

The ability for users to access data, the availability of accurate or complete data, and the availability of a methodology and quality report.

Comparability - geographical

The data are comparable across administrative regions locally, as well as at the international level.

Comparability - over time 

The survey began in 1979 as a monthly survey, and the following are the main changes that have taken place in recent years.
•    Base year 1988:
The number of goods and services included in the composition of the consumer price index was increased to 220 items.
•    Base year 1999:
The new basket included 406 goods and services.
•    Base year 2007:
The basket included 476 goods and services.
•    Base year 2013:
The total number of items in the new basket reached 489.
•    Base year 2018:
The consumer basket included 490 goods and services.
•    Base year 2023:
The consumer basket included 582 goods and services.
The publication also includes detailed historical data since 2013.

Coherence- Cross domain

Not applicable.

Coherence- Sub-annual and annual statistics 

The time series of the consumer price index was reconstructed starting from 2013 using the Classification of Individual Consumption According to Purpose (COICOP 2018) and the chain-linked methodology, with the aim of providing a consistent time series that accurately and flexibly reflects economic changes. In the reconstruction process, care was taken to maintain the consistency of the annual and monthly results with those previously published under the 2018 base year, ensuring the possibility of conducting comparisons and analyzing historical trends according to the new methodology, without compromising data integrity or losing time-series continuity.

Coherence- National Accounts 

The consumer price index was calculated, including the reference periods, classifications, and consumer basket weights, in accordance with the principles on which GDP data and national accounts are based.

Coherence- Internal 

The Consumer Price Index estimates for the reference period have full internal coherence, as they are all based on the same corpus of microdata, and they are calculated using the same estimation methods.

Accessibility and clarity

The ability for users to access data, the availability of accurate or complete data, and the availability of a methodology and quality report.

Press releases

The announcements for each publication are available on the statistical calendar as mentioned in 10.1. The press releases can be viewed on the website of GASTAT on the link: 
Press release

Publications

GASTAT issues publications and reports on the consumer price index on a regular basis within a pre-prepared dissemination plan and are published on GASTAT’s website. GASTAT is keen to publish its publications in a way that serves all users of different types, including publications in different formats that contain (publication tables, data graphs, indicators, metadata, methodology, and questionnaires) in both English and Arabic.
The results of the consumer price index are available at:
Publications

On-line database

The data is published on the statistical database:
GASTAT (stats.gov.sa)

Microdata accessibility

Accurate data is unit-level disaggregated data obtained from multiple sources such as sample statistical surveys, general population and housing censuses, and administrative systems, providing detailed information about the characteristics of individuals, families, business entities, and geographical areas, supporting the construction and development of statistical indicators and scientific research.
The different types of microdata files to meet different information needs:
•    Public use: 
It consists of sets of records containing information on individuals, households, or business entities anonymized in such a way that the respondent cannot be identified either directlysuch as: (name, address, contact number, identity number etc.) or indirectly (by combining different - especially rare - characteristics of respondents) such as: (age, occupation, education etc.).
•    Scientific use:
These files established based on specific methodology asked by data requester to extract the datasets with specific characteristics used for strategic studies and decision making as well scientific research purposes on individuals, households, and enterprises with no direct identifiers, which have been subject to control methods to protect confidentiality.
Qualified users who meet the standards and procedures of confidentiality protection can access the files of scientific use of accurate data through the platform "ITAHA" of the General Authority for Statistics, while the most sensitive data for use is shared by visiting the accurate data laboratory within a secure environment managed by the Authority.

References and standards

General standards of the statistical process: Commitment to the Generic Statistical Business Process Model (GSBPM), which provides a standardized description of the stages of statistical data production, from identifying needs to dissemination and evaluation.
Guidelines for completing the questionnaire (field researcher’s manual): Guidelines for the Consumer Price Index Survey.
Guidelines for the Classification of Individual Consumption According to Purpose (COICOP 2018): https://unstats.un.org/unsd/classifications/coicop 
The Consumer Price Index Manual 2020 issued by the International Monetary Fund (IMF), which is relied upon to ensure the quality of results and international comparability.

Quality assurance

GASTAT considers the following principles: Impartiality, ensuring that the statistical product is user-oriented, maintaining the quality of processes and outputs, enhancing the effectiveness of statistical operations, and reducing the burden on respondents. 
Data is validated through procedures and quality controls that are applied during the process at various stages, such as: (data entry, data collection, and other final controls).

Quality assessment

GASTAT performs all statistical activities according to a national model (Generic Statistical Business Process Model – GSBPM). According to the GSBPM, the final stage of statistical activities is overall evaluation using information gathered in each stage or sub-process. This information is used to prepare the evaluation report, which outlines all the quality issues related to the specific statistical activity and serves as input for improvement actions.

Confidentiality

Confidentiality - Policy

According to Royal Decree No. 23 dated 07/12/1379, data must always be kept confidential and must be used by GASTAT for statistical purposes only.
Therefore, the data is protected in the data servers of GASTAT.

Confidentiality - Data Treatment

Data were displayed in appropriate tables to facilitate their summarization, comprehension, and results extraction. Also, to compare data with other data and extract statistical meanings for the study community. It is also easier to check tables without the need to see any sensitive or confidential data, which violates the confidentiality of statistical data.

Publishing policy

Statistical calendar

The consumer price index is included in the statistical calendar.
Statistical Calendar

User access

One of GASTAT’s objectives is to better meet its clients' needs, so it immediately provides them with the results once the consumer price index publication is published.
It also receives questions and inquiries from clients about the publication and its results through various communication channels, such as:
•    GASTAT official website:  www.stats.gov.sa
•    GASTAT official e-mail address:   info@stats.gov.sa
•    Client support e-mail address:   info@stats.gov.sa
•    Official visits to GASTAT’s official head office in Riyadh or one of its branches in Saudi Arabia.
•    Official letters.
•    Statistical telephone: (199009).

Comments

The relative importance is updated annually to more accurately and flexibly reflect actual changes in consumption patterns, through scientific linking mechanisms that allow the seamless integration of updates using the chain-linked methodology, while ensuring methodological consistency and stability.