Is it too irresponsible for the plywood and MDF inspection agency to mark “only responsible for the sample”?
In many plywood and MDF inspection reports, there is a statement of “only responsible for the sample”, especially when the plywood and MDF inspection reports have qualified conclusions. Some consumers (organizations) don’t understand. They think that plywood and MDF inspection agencies can’t shirk their responsibilities. Qualified is qualified. Don’t play word games. The consumer’s accusation can be understood, which is largely the result of the inadequate work of the plywood and MDF product quality supervision department and the lack of understanding of the theory of spot check control. However, the explanation that plywood and MDF inspection agencies are only responsible for samples seems to be “shirking responsibility”, but in fact it is their duty.
On the connotation of plywood and MDF inspection institutions “only responsible for the samples”
1、 Properties and functions of plywood and MDF inspection agencies
Plywood and MDF inspection institutions are technical institutions that provide impartial data for the society, and accept the plywood and MDF product quality supervision departments (that is, departments or units that manage and supervise the quality of plywood and MDF products) to carry out plywood and MDF inspection tasks on samples. It does not have the function of supervising production enterprises. However, I do not know when the plywood and MDF inspection agencies have been “given” many powers: to determine the level of quality; Arbitration of plywood and MDF products before entering the market; The basis for punishment, etc. In reality: if plywood and MDF products are inspected as qualified by plywood and MDF inspection institutions, the quality supervision department will praise the manufacturing enterprises and allow their plywood and MDF products to enter the market for circulation and sale, otherwise they will be sealed up, investigated and punished. In other words, plywood and MDF inspection organizations have the function of supervision and the power of judgment. This function and power run counter to the market orientation of plywood and MDF inspection agencies. It is incompatible with the status of plywood and MDF inspection agencies, and is also one of the sources of misunderstanding.
In reality, many plywood and MDF inspection organizations know that they do not have the function of supervision, but they cannot explain clearly. Whether the plywood and MDF products of the manufacturer are qualified or not is not determined only by the quality of the sample, because the qualified sample is not equal to the qualified plywood and MDF products. In other words, no matter what sampling method is used, the degree of correlation between the quality of the sample and the quality of the plywood and MDF products depends on the nature of the sampling purpose, the size of the sample number, the setting of the plywood and MDF inspection plan, and the level of the risks that can be undertaken, which does not depend on the plywood and MDF inspection institutions. For example, the number of samples is determined according to the nature and requirements of the spot check, not simply according to the plywood and MDF product standards. According to the nature of the spot check, it can be divided into supervision spot check, acceptance spot check and transaction spot check. They are not determined according to the attributes of the unit performing the spot check (inspection), nor are they differentiated by subjective will. They should comply with the procedural requirements of their regulations. Even the manufacturing enterprise can conduct supervision and spot check, and the regulatory department can conduct acceptance spot check. Plywood and MDF inspection agencies only carry out plywood and MDF inspection on samples. They neither participate in the development of the sampling procedure plan, nor know the nature of the sampling, but only determine whether the characteristic values of the samples meet the specified requirements. If they rush to draw conclusions on plywood and MDF products, they will often get the result of blind people feeling the elephant, and “only responsible for the samples” is the best responsibility for the entrusting party, Avoid wrong guidance.
2、 Relationship between samples and quality of plywood and MDF products
The quality of plywood and MDF products can be reflected by whether the samples are qualified or not, but this requires a set of scientific specifications and requirements, that is, different sampling properties should comply with different sampling plans and determination procedures. In reality, sampling plywood and MDF inspection includes: supervision sampling, acceptance sampling and transaction sampling. As a plywood and MDF inspection agency, without knowing the nature of random inspection, it can only use “only responsible for the samples” to show its rigor and science.
- Supervision and random inspection
The supervision and random inspection is only a one-time random inspection. There are no special requirements for the composition of the random inspection of plywood and MDF products. However, if the sample is qualified, it cannot be determined that the random inspection of plywood and MDF products is qualified. If the sample is unqualified, it can be confirmed (the confidence probability is 95%) that the qualified rate of the random inspection of plywood and MDF products does not reach the corresponding qualified rate of the sampling plan, and it is determined as unqualified. For plywood and MDF inspection institutions, neither do they know whether the random inspection is a supervision random inspection (its nature is not based on the attributes of the inspection department, but should comply with the specific procedures of the supervision), nor do they know the size of the unqualified rate (quality level) required by the supervision, nor can they link the sample quality with the quality level of plywood and MDF products, even if they know that the random inspection is a supervision random inspection, It is also wrong to draw a qualified conclusion for random inspection of plywood and MDF products. Therefore, plywood and MDF inspection agencies have to show the prompt of “only responsible for the sample”, otherwise it is easy to mislead others, and even become the root cause of making wrong cases.
- Acceptance spot check
The acceptance random inspection shall be carried out continuously (generally more than 10 times). The plywood and MDF products to be inspected must be plywood and MDF products of the same manufacturer, model and batch. If the sample is qualified, the batch of plywood and MDF products will be accepted. If the sample is unqualified, the batch of plywood and MDF products will be rejected. It can ensure that the sum of the received batch of plywood and MDF products reaches the specified qualification rate, and it is determined as qualified. As an inspection agency for plywood and MDF, it is impossible to carry out continuous acceptance spot check for the manufacturer. Even if it is qualified in one acceptance spot check, it is only the sample that is qualified, which cannot prove that the batch of plywood and MDF products are qualified. The acceptance spot check is to ensure that the unqualified rate of the received batches of plywood and MDF products is controlled below a specified value through continuous plywood and MDF inspection, so as to achieve the purpose of checking the quality of plywood and MDF products, rather than relying on the way that the qualified sample equals the qualified plywood and MDF products.
- Transaction spot check
The transaction spot check is generally only a one-time spot check, but the number of samples for spot check is relatively large. If the sample is qualified, the transaction will be successful, that is, the plywood and MDF products will be qualified, otherwise the transaction will fail. However, the plywood and MDF inspection institutions can’t know the risk of the transaction success, so it is impossible to set a spot check plan for both parties. It is obviously inappropriate for plywood and MDF inspection agencies to substitute qualified samples for the risk that both parties are willing to accept, which may lead to dissatisfaction of both parties. The determination of the transaction spot check results can only be determined by the two parties according to the sample quality conditions set by both parties in advance, that is, the determination of whether the transaction batch of plywood and MDF products are qualified according to the qualified quantity determined by the plywood and MDF inspection agency.
From the above analysis, no matter what kind of random inspection, the sample quality is not equal to the quality of plywood and MDF products, which is essentially different. In other words, even the plywood and MDF inspection commissioned by the supervision department cannot guarantee that the sample is equal to the plywood and MDF products, and the sample submitted by the manufacturer itself cannot be equal to the plywood and MDF products. Therefore, it is absolutely not easy to draw a qualified conclusion for plywood and MDF products based on the quality of the samples. It must be noted that “only responsible for the samples”, so as to show their work nature and attitude.
3、 The role and significance of “only responsible for samples”
Some consumers often regard plywood and MDF inspection agencies as the dispatched agencies of the quality supervision department, and always hope that the plywood and MDF inspection agencies have a clear conclusion on the quality of plywood and MDF products, not just the judgment of samples. They believe that the plywood and MDF products can be judged by random sampling in the same batch of plywood and MDF products, that is, the sample is representative (or equivalent) of plywood and MDF products. In fact, this is caused by misunderstanding and misuse of big data law in statistical theory. In fact, the same batch is a special term used by manufacturing enterprises to facilitate statistics and management, that is, plywood and MDF products produced in many identical environments can not guarantee that the quality characteristic values of plywood and MDF products in the same batch are the same, while random sampling is only a sampling method that eliminates human factors and has a certain probability of acquisition, and is not the condition and method that samples are equivalent to plywood and MDF products. Using random sampling in the same batch of plywood and MDF products to prove that the sample is equivalent to plywood and MDF products is a trick of stealing the beam and changing the column. It is a typical behavior of blind people touching the elephant. Therefore, plywood and MDF inspection agencies have clearly recognized this point, and cannot be influenced by these misconceptions. It shows that “only responsible for the samples” is not only telling the client the nature of the plywood and MDF inspection work, but also expressing sufficient confidence in the data obtained from the plywood and MDF inspection, and also popularizing the theoretical knowledge of random inspection and control, so that consumers and the client can understand the rigor and science of the plywood and MDF inspection organization.
4、 Conclusion
The statement of plywood and MDF inspection agency that “only responsible for the sample” is not a shirking of responsibility, but an attitude. It tells people to know the attributes of plywood and MDF inspection agencies when interpreting plywood and MDF product inspection reports, and not to be confused by people with ulterior motives. It also reminds the quality supervision department to correctly apply plywood and MDF inspection reports, conscientiously perform its own responsibilities, and make supervision and management and plywood and MDF inspection work more scientific and standardized.
