ETS Conformance

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Conformity for a quantitative quality element

The Regulation defines 6 quality elements, grouped into two conformance classes. Based on the item conformance verdicts issued for the various criteria during the item inspection, verdicts will be made on each conformance class.

All quality elements have been expressed in quantitative terms and require measuring or counting. To apply the verdict on each quality element will involve counting non-conforming items or non-conformities before applying the limiting quality (LQ) indexes from ISO 2859-2. Such indexes model the statistical relationship between an expectation, the required sample size and the resulting counts to provide acceptance numbers that represent a statistically robust verdict on conformity.

The table below offers an extract (relevant part for current LPIS sizes) of the sampling table of ISO 2859-2 for the LQ indexes 2 and 12.5.
n= sampling size, AC= acceptance numbers.

Table 1

Lot Size n/AC LQ 2 LQ 12.5
35001 -> 150000 n 500 200
AC 5 18
150001 -> 500000 n 800 200
AC 10 18
> 500000 n 1250 200
AC 18 18


Conformance class 1

Context

The conformance class 1 means to “assess the quality of LPIS”, and counts non-conforming items (either reference parcels or, where applicable, crop aggregates) This counting of items has been used for all quality elements in the past and is still relevant for the first three quality elements (QE1, QE2 and QE3). Furthermore, counting items offers a straightforward entry for the LPIS upkeep processes.

Table 2

Element Value Description Expectation LQ index
1 QE1 assesses the maximum eligible area of the system - -
QE1a absence of bias (i.e. accuracy) of the land represented in the LPIS as a whole. >= 98%,<= 102% -
QE1b1 parcel level precision of the land represeneted in the LPIS as a whole: overestimation LIB >= -2% -
QE1b2 parcel level precision of the land represeneted in the LPIS as a whole: underestimation UIB <= 2% -
2 QE2 assesses individual parcels with correctness issues. - -
QE2a1 Proportion of RPs (whole set of data) with incorrectly recorded area or “contaminated” or with ineligible features <5% 12.5
QE2a2 Proportion of RPs (>0.1 ha) with incorrectly recorded area or “contaminated” with ineligible features <5% 12.5
QE2b Distribution of RPs, according to the correctness of the eligible area recorded - -
QE2c Number of non-conforming reference parcels in LPIS with classification error <5% 12.5
3 QE3 Number of reference parcels that have functional issues ("Critical Defects") <1% 2

Expectations

As indicated in the table above, the expectations remain set at <5% (for QE2) and <1% (for QE3) non-conforming items. These expectations are tested through acceptance numbers for indexing with limiting quality LQ12.5 and LQ2 respectively.

An example: the quality expectation "less than 1%" is indexed at a LQ 2 so for a population that counts 300000 items, the table indicates that 800 items need to be inspected and that no more than 10 non-conforming items or non-conformities can be identified. The set will fail the measure as soon as 11 or more non-conformities or non-conforming items are counted in that sample of 800. Note that 11/800 is 1.4%, the 0.4% difference from 1% accomodates the statistical robustness given the sample size.

Procedure

Diagram 4 illustrates the procedure to aggregate observations for the conformance class 1 assessment.

Report LPIS conformance class 1a.png

Diagram 4: conformance class 1 testing

Conformance class 2

Context

Conformance class 2 aims to "identify possible weaknesses", and this requires a broader system wide analysis, beyond the individual item or reference parcel. This is most obvious for QE4 which analyses the LPIS processes and design as factors for creating quality problems. For instance, a single, large parcel can be contaminated, can have critical defect (for example, multi-parcel), and can have its land wrongly classified. Although this represents a single non-conforming item, it does reflect three different system weaknesses.

Table 3

Element Value Description Expectation LQ index
4 QE4 Categorization of the non-conformities <5% 12.5
5 QE5 Ratio of total declared area in relation to the total area recorded for the area conforming RPs - -
6 QE6 Rate of non-conforming reference parcels due to undetected and unaccounted land cover change, as observed in ETS, accumulated over the years < 25% -

Expectation

For QE4, the expectation remains at <5%, however no longer counted as non-conforming items but counted in terms of non-conformities per 100 items. This expectation is tested through the acceptance number for indexing with limiting quality LQ12.5.

Procedure

Diagram 5 illustrates the procedure to aggregate observations for the conformance class 2 assessment.

Report LPIS conformance class 2.png

Diagram 5: conformance class 2 testing


Practical guidelines

The number of inspected parcels (sample size) has been determined by indexing on LQ 2 as required for QE3 (i.e. parcels checked for critical defects) and by indexing on LQ12.5 as required for QE2 (i.e. parcels measured). These separate determinations yield a different sample size and the inspection should continue until the number of inspected and measured parcels reaches the number required for each seperate index respectively.

The Member State shall, for quality elements 2,3, and 4

  1. use tables 2 and 3 to determine the Limiting Quality for a particular quality element based on the given expectations;
  2. use table 1 to determine the sample size and acceptance number (AC) for a particular quality element;
  3. when for any quality element the prescribed sample size is smaller than the actual sample size as inspected during the ETS, increase the initial acceptance number given in the table proportionally to the ratio of final sample size to pre-scribed sample size. Truncate (DO NOT round) to an integer number;
  4. when the observed number on non-conforming items exceeds the acceptance number derived in point 2 (or 3 if applicable), assign ‘non-conforming’ for that quality element in the ETS scoreboard'


The Member State shall for quality element 1 and 6

  1. use tables 2 and 3 to determine quality expectations for the particular quality element;
  2. assign "non-conforming" to either element in the ETS scoreboard when its reported value exceeds the expectation.


Table 4 (given below) provides an overview of the 3 main parameters needed for each of the quality elements to come to a given conformance verdict.

  1. Data Quality scope (DQ scope) - the temporal and spatial extent identifying the data on which given data quality is to be evaluated. For example the Quality Element 3 (Critical Defects) is calculated from all reference parcel being inspected during the ETS. Thus, the Data quality Scope for QE 3 is "All inspected reference parcels"
  2. non-conforming items - number of either non-conforming reference parcels or non-conformities found during the particular element. This number will, where appropriate, be the nominator for the calculation of the percent non-conforming (for QE1 and QE6) or the total number of non-conformities found in the sample (for QE2, QE3 and QE4)
  3. total number of relevant items in the sample - number or items that were subject for this particular element. The number is mostly, but not always, equal to the DQ Scope. This number will, where apropriate, be used as the denominator for the calculation of the percent non-conforming and proportional acceptance number.

Table 4

Quality Element Reported Items Data Quality Scope Non-conforming items/Observed items (nominator) Total relevant items (denominator) Type of reported value ETS Annex I Alias
QE1a and QE1b Rate of correct eligible hectares found with respect to the total number of eligible hectares currently recorded in the LPIS. All measured reference parcels with etsReferenceArea that equals the maximum eligible area (MEA) All eligible hectares found during ETS on the reference parcels from the data quality scope All eligible hectares recorded for the reference parcels from the data quality scope Percentage LPIS_RP_MEA; LPIS_RP_MEA_B
QE2a Number of area-based non-conforming Reference Parcels (incorrectly recorded area or contaminated with small eligible features) All measured reference parcels with etsReferenceArea that equals the maximum eligible area (MEA), minus those with areas not directly comparable Number of area non-conforming reference parcels from the data quality scope, with etsReferenceArea BIGGER THAN or EQUAL TO 0.1 ha see "Data Quality Scope" a number LPIS_RP_NEA_B
QE2b Distribution of the reference parcels in LPIS, according to the correctness of the eligible area recorded. All measured reference parcels with etsReferenceArea that equals the maximum eligible area (MEA), minus those with areas not directly comparable - - - LPIS_RP_SEA
QE2c Number of non-conforming Reference Parcels with classification error. All measured reference parcels, minus those with areas not directly comparable Number of area non-conforming reference parcels with classification error from the data quality scope[1] see "Data Quality Scope" Percentage LPIS_RP_CLS
QE3 Number of Reference Parcels that have critical defects All inspected reference parcels Number of Reference Parcels having critical defects see "Data Quality Scope" a number LPIS_RP_CRA
QE4 Categorization of non-conformities (Abundance of the causes for occurrence of non-conformities in the reference parcels) All non-conformities (weaknesses) found on all inspected RPs Number of non-conformities per cause All inspected reference parcels a number for each cause separately LPIS_RP_CEA
QE5 Ratio of the total declared area in relation to the total area recorded for the conforming reference parcels All measured and area-conforming (QE2a) reference parcels V1:All eligible hectares declared in the assessment year for the RPs in the data quality scope; V2: All eligible hectares declared in the assessment year for the whole IACS V1:All eligible hectares recorded in the LPIS for the RPs in the data quality scope; V2: All eligible hectares recorded in LPIS for the whole IACS Percentage LPIS_RP_DCA
QE6 Cumulated rate of non-conformities due to undetected or unaccounted land cover changes All non-conformities with missed land update found from all inspected RPs All non-conformities with missed land update found for the year of assessment All inspected reference parcels in the years of assessment Percentage (cumulative rate). Rate from previous years should be added starting from the last systematic update of the LPIS. See also the Example_of_QE6_calculation LPIS_RP_CMC


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<references>
  1. Except those with: (1) with only one type of agriculture land cover category recorded in the LPIS AND (2) same category found on the LUI during the ETS