Presentation on theme: "CES III. Montreal, June 2007 Jorge Saralegui-Gil Environmental Stats. and Accounts. INE. Madrid (Spain)"— Presentation transcript:
CES III. Montreal, June 2007 Jorge Saralegui-Gil Environmental Stats. and Accounts. INE. Madrid (Spain) email@example.com
Special Features of Environmental Surveys to Establishments The scenario: Sharp increase of information needs; Sustained pressure of users demand for environmental statistics. Administrative sources clearly insufficient Statistical infrastructure as the classifications of characteristics, the delimitation of the observation units and their population frames, are not appropriately integrated within the general statistical system. Physical accounting not fully integrated in bussines practices. Survey sampling methods and techniques still in a primary step of research in the field of physical flows for environmental statistics.
INE (Spain) ENVIRONMENTAL SURVEYS In consonance with their internal organisation, INE Env. surveys are often classified into three thematic blocks -Water Surveys -Waste Surveys -Environmental Protection Expenditure Surveys. To satisfy Accounts needs : mixed type modules, i.e. environmental expenditure module in the Waste Generation Survey on the Services Sector. Co-ordinated with business surveys to avoid repeated selection
Water related Surveys Administrative sources provide satisfactory information related to extraction and availability of stocks ( wholesale water ). Usually, they also provide satisfactory information regarding quality variables. In many important instances statistical needs are not satisfied by administrative sources. Those are mainly related to water supply, use, and sewage generation. Statistical detail ( quantity, quality, costs) at the level of economic activity sectors is also needed (surveys to establishments).
Water use in Agriculture (I) Mixed Frame: River Basin Authorities, (wholesale water, abstraction) Irrigators associations (distribution, irrigation techniques, turnover) Agricultural Holdings (crops, self supply, costs). Area frame Difficulties to avoid duplicates of water flows supplied to agr. holdings.
Water use in Agriculture (II) - The basic step in the estimation procedure for the SWUA uses irrigated regional total area S, classified according to the irrigation technique k (leaking, sprinkling or gravity) as exogenous variable for calibration purposes. -A correction c is needed to cope with self-supplied water a by holdings which consider the externally supplied water a insufficient. Estimates combine results of the Survey on Water Use in Agriculture (INE), the water use module within the Survey on Waste Generation in Agriculture (INE ) and the Area Frame Survey (Min. of Agric.).
Non irrigation water statistics (I) Considered as public services, its final responsibility is entrusted to local authorities. Very complex management structure. Ad hoc observation units: Water Managers (establishment type unit) in a domain. Mixed frame for the Survey on Water Supply and Treatment : The database links territorial districts with microdata identification of the corresponding CBR units. Three flow types (water abstraction, water supply and waste water collection and treatment) constitute estimation targets for establishment surveys on the sector.
Non irrigation water statistics (II) Take-all strata H: Frame units serving medium and large districts. For the remaining water managers (i,j below) a ratio estimator is used ; it is based on the number of residents ( p) of the municipalities being served by them (with a correction coeffic. c whenever the service is shared with other managers).
Sewage Treatment. Exogenous (Min. of Env.) Equivalent population is used instead to estimate the total population receiving the waste water treatment service in the domain. The concept of equivalent inhabitant is defined as the biodegradable organic load carrying a biochemical 5-day oxygen (DBO5) demand of 60 gr. of oxygen a day. Equiv. Pop. can be calculated at the micro level for responding units (water managers). Population figures cannot be used as totals for calibration (coverage unknown )
Water Use by Economic Activity Sectors The statistical study of water is completed through an special module on water related questions, included in the waste generation survey questionnaires, addressed to the different economic sectors. This module is crucial to provide estimates for water satellite accounts. The relevance of the sewage treatment questions, also included in that module, is to be underlined because of the potential environmental effects of sewage and its treatment in some industrial branches.
Waste Generation Surveys (I) Estimates presented in satellite accounts (material flows accounts, satellite accounts on waste). Structural statistics (to produce both environmental indicators and reports). Specific sections of sustainable development indicators systems. Other fields of waste statistics refer to the type of treatment applied to waste, and the treatment facilities characteristics. Information needs on waste are approached by the statistical system in the context of :
Waste Generation Surveys (II) Waste generation either by waste category or economic activity branch can be estimated through samples of the same type of units as those addressed by other structural surveys. Ad hoc data collection procedures in particular sectors ( i.e. M. of Defense ) A sample of establishments drawn from the CBR is combined with a coordinated subsample of establishments from annual structural bussines surveys.
Waste Generation Surveys (III) Administrative regulations (particularly demanding for hazardous waste) use LoW (List of Waste, activity oriented categories). Statistical system (in EU) works with EWC-Stat (product oriented). Technical difficulties to treat blank cells either as a partial non- response or as a zero value. Strategic mandates to reduce reporting burden. Regional estimates are highly demanded but the estimation cannot be efficiently carried out using direct estimators based on small samples Quality challenges : Reporting units (establishments, holdings ) must cope with a double coding problem, related to the use of different classifications.
* Estimators of waste type X at the regional level C are of the post stratified ratio type. An ancillary variable v is introduced (sales, production, employment ) whose value is known for every sample unit i of stratum h in post stratum A, as well as its exogenous totals from the active population survey and from the structural annual business surveys respectively, as follows: Waste Generation Surveys (IV)
* It becomes necessary for some wastes to make use of a synthetic estimators based on nationwide means in order to impute the latter to a post stratum A within the domain C. Waste Generation Surveys (V)
Waste generation Complementary survey techniques -Partial non_response imputation in waste generation surveys is particularly troublesome. -It is carried out, first, through a selective approach to a subsample. -In a second step substrata within which waste generation appears to be homogeneous for specific waste categories are identified. -Multi-year cummulated vector of frecuencies of the presence or absence of particular wastes within strata provides a basis for non zero imputation. For the survey on Waste Generation in Agriculture estimations rely on external marginal values such as cultivated land per crop and livestock figures.
Urban Waste (I) -Take-all strata coverage amounts to more than a 40% of the territory as a whole, thus estimation-related biases are fairly bounded. -As with the sewage treatment, the use of complex estimation procedures within sampling strata becomes necessary as an exact knowledge of territorial coverage for sorting residues collection is lacking. The Frame for the Collection and Treatment of Urban Waste Survey (UWS hereafter ) consists of territorial units linked to the establishment-type units supplying the service
Urban Waste (II) As far as the distinction urban waste versus household waste is concerned, the procedure combines estimations from the UWS and from waste generation surveys : In the waste generation survey questionnaires addressed to the service sector establishments and institutions, one section concerning the destiny of waste is included in order to know whether the waste is handed over to either a waste municipal manager or to a non-municipal one (licensed private managers) In doing so it becomes possible to estimate the fraction of waste collected by municipal managers, and consequently the amount of a particular category of waste generated by households, derived from the UWS estimated totals.
Waste Treatment (I ) - In a first step, a sample of licensed waste managers is drawn- from administrative records as provided by the regional environmental authorities. -Both the number and total capacity of several types of waste treatment facilities are externally available for each domain. It is used as an ancillary variable when estimating total treated waste Perhaps the most important area of waste statistics. Two approaches to frame building: facility-oriented approach ; the licensed waste managers approach.
x denotes the amount of waste that have been treated by manager j of the frame, in stratum h by treatment type k. (either recycling, land filling, incineration with or without energy recovery, etc.). - Design weight w of unit j is adjusted within the stratum h by the coefficient of non response /out of scope c. t refers to maximum capacity for treatment k, as stated for those facilities managed by a sampled unit. - T refers to total treatment capacity for type k, as given by external sources, within the estimation domain. The estimator is of the type Waste Treatment (II)
Other environmental statistical operations To estimate the use of hazardous chemical products in agriculture Holdings fill out an open answer question set where they are inquired on the commercial brand, amount, crop and license code for each plan protection product used. To obtain estimates at active substance level a subsequent computer procedure is carried out by merging administrative records of the identified ppt. Supply-side environmental protection statistics : production estimates from samples of establishments are to be combined with estimates for the demand-side (expenditure) variables, along with administrative sources or other external information such as data from sector-related entrepreneurial associations.
Some conclusions (I) Heterogeneous nature of environmental statistical operations which lie typically halfway between common practices for national accounting and the traditional survey-based statistics. In order to avoid double counting, underestimates or omissions, when estimating physical flows related to generation and treatment of either waste or water, work teams for environmental surveys have to be able to act with high methodological flexibility. They do need to be provided with sufficient resources in order to build survey frames and set complex designs following mixed procedures, which combine statistical registers and administrative sources with one or even more surveys, in one or several steps.
Some conclusions (II) Placing the personnel that carry out environmental accounts, indicators and surveys in the same technical units turns out to be very convenient. Staff in charge of data collection have to be aware that physical accounting will still take some time until it is familiar to business practices, then adapting instruments to this (hopfully) transitory scenario is of crucial importance for quality of environmental statistics. These facts condition altogether the special profile within the statistical system of the environmental statistics area that needs to be taken into account by the statistical offices any time they design their medium or long term operating plans.