# An Assessment Model for Air Passenger Risk Classification
## 2 Assessment Model for Air Passenger Risk Classification  
### Index System of Passenger Risk Assessment  
The index system of passenger risk assessment is the foundation of assessing passengers' risk. There are many methods to construct the assessment index system, such as Delphi method, analysis method, cross method, comprehensive method and grouping method of index attribute. Although some scholars have carried out relevant research, there is no uniform standard for the establishment of passenger risk assessment index systems. Moreover, there are some problems in the existing research. For example, the established index systems are too huge. In addition, the correlation of some indexes is high. Passenger risk assessment mainly analyzes the risks that passengers have that endanger aviation safety. It is similar to the credit risk assessment of individuals by financial institutions such as banks. In addition, the personal credit assessment system is relatively mature. Therefore, this paper uses the comprehensive method to scientifically and systematically analyze the passenger risk assessment index systems in [21,22], and the current personal credit assessment index systems, and make further improvements. The index system of passenger risk assessment established in [21] includes 5 first-level indexes and 47 second-level indexes of natural condition, occupation, economic situation, credit standing and flight situation. The index system of passenger risk assessment established in [22] includes 4 first-level indexes and 30 second-level indexes of basic situation,economic situation, public records and flight information. The above indexes are classified and sorted, and the basic background, personal status, economic situation, personal conduct and civil aviation travel record are selected as the first-level indexes, in which the basic background is the inherent attribute of passengers, the personal status is an important index to evaluate the stability of passengers, the economic situation is an index that indicates the economic level of passengers, the personal conduct is an index that describes the behavior and morality of passengers, and the civil aviation travel record reflects the situation of passengers' civil aviation travel. According to the second-level indexes of natural condition, occupation situation in [21] and basic situation and economic situation in [22], gender, age, nationality and education are selected to describe the basic background information of passengers. In addition, occupation, place of residence, religious belief, marital status and state of health are selected to reflect the personal stability of passengers. The index of occupation is used to replace the relevant indexes such as industry, occupation, and professional title, which reduces the number of indexes while ensuring the comprehensiveness of the evaluation. Based on the personal credit evaluation system, redundant indexes such as family structure and dependent population are excluded, and the index of marital status is used to describe the marital and family situation of passengers. In terms of the economic situation, there are some indexes in [22] that are not suitable for describing the economic situation, such as family structure and supporting population. Therefore, following the principle of independence, the index of total assets is used to replace deposit, housing and other indexes of movable and immovable property on the basis of [21] to ensure the accuracy of the evaluation results. Moreover, the indexes of annual income, debt and insurance amount are retained. When selecting the indexes to evaluate passengers' conduct based on the credit indexes in [21] and the public record indexes in [22], records of civil judgment, records of administrative penalty, records of criminal punishment and other similar indexes are combined into the index of criminal records. In addition, overdue records and tax arrears are classified as default to avoid excessive indexes affecting the efficiency of evaluation.