Calculating methods for determining the quality of goods, Expert...

10.3. Calculation methods for determining the quality of goods

Calculating methods determining the quality indicators of goods are based on the use of theoretical and stochastic and (or) empirical dependencies of the product quality indicators on its parameters. They are used in the design of goods or when the product can not be the object of experimental research.

Calculation methods are used to determine the values ​​of performance indicators, reliability, durability, maintainability, maintainability of non-food products, food (energy) value of food products, as well as to identify the theoretical energy value of food.

Energy value - is the amount of energy that is produced by the biological oxidation of fats, proteins and carbohydrates contained in foods. It is expressed in kilocalories (kcal) or kilojoules (kJ).

The energy released during the oxidation of 1 g of fat is 9.0 kcal, 1 g of carbohydrates - 3.75 kcal, 1 g of proteins - 4.0 kcal, 1 g of organic acids - 3.0 kcal/g, 1 g ethyl alcohol - 7.0 kcal/g. To obtain the energy value in SI units, the conversion factor should be used: 1 kcal = 4,184 kJ. The energy value of food is calculated per 100 g of edible part of the product.

Theoretical caloric value is calculated as the product of the caloric content of nutrients and the percentage of the corresponding nutrients. The sum of the products obtained is a theoretical caloric content of 100 g of product, knowing which, it is possible to determine the caloricity of any of its quantity (300 g, 1 kg, etc.). Based on the theoretical caloric value, the practical (actual) caloric value is calculated by multiplying the theoretical caloric value by the digestibility in percent and dividing the product by 100.

As an example, we give the average chemical composition of cow's milk (%) according to the reference data:

- fat - 3,2; proteins - 3.5; milk sugar - 4,7; ash - 0.7;

- caloric content of fats in 100 g of milk: 9 · 3,2 = 28,8 kcal;

- caloric content of proteins in 100 g of milk: 4 · 3,5 = 14,0 kcal;

- the calorie content of carbohydrates in 100 g of milk: 3.75 · 4.7 = 17.6 kcal.

Theoretical calorie content of 100 g of milk will be: 28.8 kcal + 14.0 kcal + 17.6 kcal = 60.4 kcal.

The theoretical caloric content of a glass of milk (200 g) will be: 60.4 · 2 = 120.8 kcal = 505.4 kJ.

The actual calorific value of 100 g of milk is: (28.8 * 94): 100 + (14.0 * 84.5): 100 + (17.6 * 95.6): 100 = 54.73 kcal = 229 kJ.

10.4. Expert methods of determining the quality of goods

1. Formation of a working group 2. Formation of an expert group

3. Determining the nomenclature of product quality indicators

4. The choice of evaluation methodology

5. Preparation of questionnaires and explanatory notes for an expert survey

6. Expert poll

7. Processing expert judgments

8. Analysis of results

9. Logging

Expert methods are used when it is impossible or difficult to use more objective methods (measuring or calculation) to determine the aesthetic and ergonomic indicators of non-food products and quality indicators of food products, established organoleptic method. These methods are based on determining the values ​​of the quality indicators of goods by analyzing the qualitative and quantitative assessments of experts. The quality of goods is determined by an expert commission, which consists of expert and working groups. The working group organizes the procedure for expert discussion, questioning, mathematical and statistical processing of results, analysis of expert group assessments.

Peer Review Algorithm

1. Working group formation

2. Formation of an expert group

3. Determining the nomenclature of product quality indicators

4. The choice of evaluation methodology

5. Preparation of questionnaires and explanatory notes for an expert survey

6. Expert poll

7. Processing expert judgments

8. Analysis of results

9. Logging

Experts have to consider the problem presented before a judgment is made. Therefore, for carrying out the procedure it is necessary to prepare information materials, available statistical data, reference materials and product samples.

Data on products must be versatile and neutral. The working group prepares in advance the questionnaires for experts. Depending on the method, they can be with open and closed questions. These materials should contain an indicative list of evaluated indicators and the order of their assessment, as well as indicative characteristics of the baseline values ​​for each level of graduation scales.

The answer can be given in the form of judgments, pair comparisons, ranked series, in points or in the form of an absolute score. The procedure itself is carried out by an independent moderator (the head of the procedure), who controls compliance with the regulations, distributes materials and questionnaires, but does not express his opinion.

The number of experts involved can be limited and unlimited. Usually, 5 to 12 experts are invited with special knowledge, assessment skills, experience in areas relevant to the tasks to be accomplished. It is necessary to take into account the moment of personal interest, which can become a significant obstacle to obtaining an objective judgment. When selecting experts, different methods are used. The most common method is the Ball, when the most respected specialist recommends a number of others and further along the chain, until the necessary team is selected.

To summarize the opinions of experts on the nomenclature of indicators, their baseline values, index weighting factors, scoring range, terminology, gradation of products by quality categories, use discussion and voting methods (interrogation with interaction) or averaging method (interrogation without interaction). In the first case, the generalized opinion of the expert group is revealed by a majority vote (at least two thirds).

The number of technical experts of the working group depends on the amount of work performed by the expert commission. Technical workers organize a survey of experts, conduct processing of the results. Depending on the survey method, the technician enters or does not come into contact with the expert, if necessary, explains to him insufficiently understandable questions. In the process of the survey, the technical worker should not make expert comments on his answers so as not to impose his opinion. One technician can interrogate and process the results of the assessment of 7-10 experts.

To collect expert data, the following survey methods are used:

- the expert independently, using an explanatory note, fills out the questionnaire and sends it or sends it to a technical worker or fills in an online questionnaire;

- the expert fills in the questionnaire during the conversation with the technical worker (questionnaire-interview).

The latter method is preferable, as it allows to obtain more complete information and reduce the probability of errors. Within the expert method, a score can be scored.

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