Data quality, concepts and methodology: Concepts and methods

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This publication represents a small portion of information available from Canada Food Stats, a CD-ROM product. The powerful and friendly system gathers data from across Statistics Canada and even includes data from other organizations. It contains information on food available for consumption, prices, nutrition, supply and demand, as well as data on the food industry, processing, employment, productivity, trade and much more. In addition, Canada Food Stats provides a reservoir of written articles and analysis relevant to food from production to processing to consumption.

Data presented in this bulletin are compiled from a wide variety of sources, both survey and administrative, and from various divisions within Statistics Canada along with other government departments. More information can be obtained from the Statistics Canada web site or by contacting the Agriculture Division directly. As this bulletin features food statistics, a summary of the concepts and methods used for these data series has been provided. A detailed version of the concepts and methods is available on the Canada Food Stats CD-ROM.

Statistics Canada’s Agriculture Division has produced data depicting the amount of food that is available for consumption from the Canadian food supply as far back as 1960. Food available for consumption does not account for losses in stores, households, private institutions or restaurants. Estimated quantities of food available adjusted for losses are adjusted for retail, institutional and household, including cooking, storage and plate loss.

The nutrients available data are derived by applying nutritional equivalent factors to the retail weight of per capita food available data. The Food Bureau of Agriculture and Agri-Food Canada developed these factors in cooperation with Statistics Canada. The factors were applied to each food or beverage type and then summed to derive subtotals or totals. These factors remain consistent over time starting in 1976. Consequently, the nutritional data are a subset of the Food Available in Canada data series. This data series is more correctly termed per capita food available.

The nutrients available adjusted for losses is a proxy of fork level consumption based on food supply data. They have been derived by adjusting the nutrients available from the Canadian food supply to account for retail, institutional, household, cooking and plate loss. As the factors used to adjust the food available data are estimates themselves, considerable caution should be used when working with the data — the data should be viewed as experimental.

The food available refers to the amount of food available for consumption and is derived residually using supply-disposition tables. All components of supply are added together and all uses (disposition) other than human consumption are deducted. The resulting amount is assumed to be available for human consumption.

To calculate total supply, beginning stocks, production and imports are added together. Net supply is then derived by subtracting disposition items including exports, manufacturing uses, feeds, waste and ending stocks. The net supply is divided by the Canadian population at July 1 to obtain per capita values or disappearance per person.

The data for the numerous supply-disposition tables are obtained from a myriad of survey, administrative and other sources. Each food commodity table is unique.

In general, beginning stocks are those quantities of fresh and frozen food products held in storage at January 1 while ending stocks refer to year-end inventories (December 31). Stock and production data are obtained through surveys of producers and food processors. Import and export data are provided by the International Trade Division of Statistics Canada. Manufacturing data include requirements for processing, seed, animal feed and industrial use. Processed foods are then accounted for directly.

Traditionally, the waste factors attempt to account for quantities removed during processing or lost in storage. They do not allow for losses in stores, households, restaurants or institutions during storage and preparation or for unconsumed food. Consequently, the food available data are sometimes referred to as “apparent” to remind users of this data limitation. The nutrients available adjusted for losses are not apparent but rather represent a proxy of consumption as the food available data were adjusted to account for food losses not previously accounted for.

The new waste adjustment factors account for losses at the retail and consumer levels, including institutions, restaurants and households. The factors attempt to account for losses or waste from storage, in the preparation of food and from the plate. The factors were provided, with appreciation, from the United States Department of Agriculture.

All of the nutrient factors and waste adjustment factors are based on weight. Consequently, the waste adjustments have a limitation in that they may only partially account for losses of some nutrients as a result of cooking. For instance, more (or less) fat, fat soluble nutrients or water soluble nutrients may be wasted depending on the methods used in preparation and cooking. Although every attempt has been made to adjust the nutrient data to approximate consumption, the data are estimates, a limitation that readers should keep in mind when working with the files. Further, these data refer to nutrients available from food and beverages and do not account for nutrients that may be provided by dietary supplements or from the water supply.