Are security checks in Beijing subway justified?

Liang Pinghan, Professor at Sun Yat-sen University, calculates financial and time burdens on Beijing subway passengers and analyses the trade-off between safety and efficiency.

I commute daily on Beijing Subway Line 1, so I am well-acquainted with subway security checks in Beijing and across China, as the procedures are generally consistent. The process involves three steps: baggage goes through an X-ray scanner, passengers walk through a security gate, and subway staff hand-check with a portable metal detector.

Critics of subway security checks highlight overstaffing and the casual execution of procedures, rendering their presence largely ceremonial. They also complain about wasted time and public money, and the catalogue of prohibited items, which include not only guns, explosives, and petrol but also mundane items like over two lighters, nail polish over 20ml, kitchen knives, utility knives, and other sharp or blunt instruments that can cause injuries.

Those defending subway security checks often cite the employment opportunities they create and their role in preventing and deterring attacks, suggesting this is why China has been free from terrorist attacks for years. More interesting answers can be found on Zhihu, the Chinese equivalent of Quora. Some users attribute these checks to subway authorities avoiding blame, while others see national security plots. One comment, responding to complaints about subway security checks with "I suggest armed security with live ammunition!!! It looks like these bastards are definitely going to cause trouble," garnered over 12,000 likes.

Recent incidents, including the knife attack at a Shanghai metro station and additional stabbings in a Jilin park and Suzhou bus station, have intensified the debate about the effectiveness of subway security checks and the broader security surveillance system in China.

—Yuxuan Jia

The following article is written by Liang Pinghan, Professor at the School of Government, Sun Yat-sen University. Originally published in Issue 19 of PKU Financial Review, it remains available on both the official website and the official WeChat account of the HSBC Financial Research Institute (HFRI) at Peking University.

Liang believes the question boils down to a trade-off between safety and efficiency. He estimates subway security checks cost 13.4 billion yuan annually for personnel nationally, and cause a 2.677 billion yuan loss in passenger time in Beijing each year. Despite these high costs, the benefits are minimal, and more cost-effective alternatives like enhanced video surveillance and police patrols could better deter crime.

Liang also notes that other safety measures, such as road cameras, may be driven by revenue generation rather than public safety, thus causing public dissatisfaction. He advocates for a balanced approach that carefully evaluates the costs, benefits, and potential negative impacts of security measures.

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安全的成本

The Cost of Being Safe

The 2023 blockbuster film Oppenheimer highlights the persistent tension between safety and efficiency. During the Manhattan Project, Los Alamos was initially divided into sections with no communication between them, adhering to strict security protocols. However, Oppenheimer believed this approach would severely hinder efficiency. Given that the United States was already behind Germany in developing the atomic bomb, rigid adherence to these security measures seemed destined for failure. Oppenheimer's insistence allowed for necessary information exchange within Los Alamos, significantly accelerating the research process. While it is unclear if this contributed to the Soviet Union later acquiring atomic bomb secrets, this approach undoubtedly accelerated the research process, enabling American scientists to achieve groundbreaking progress and become the first to develop the atomic bomb.

The experience of the Manhattan Project demonstrates the trade-off between safety and efficiency. While safety and development are not inherently contradictory, specific safety measures should be evaluated based on their costs and benefits. Take subway security checks, for example. As of October 2022, 51 cities in China (excluding Hong Kong, Macau, and Taiwan) had operational subways with routine security checks at entrances, involving equipment like X-ray machines and security gates to inspect passengers and their belongings. So, what are the costs and benefits of these routine subway security checks?

Without national-level statistics, one can only estimate. The number of subway security checkpoints correlates highly with, or is equal to, the number of subway entrances. According to Amap, a popular map service in mainland China, by the end of 2021, there were 18,656 subway entrances nationwide. Security personnel work underground without natural light, so their shifts cannot follow a standard eight-hour workday. Assuming subways operate 15 hours a day and require three shifts, with at least three security personnel per shift, each subway entrance would need at least 12 security personnel per month, considering weekends and rotation. Thus, all subway entrances nationwide would require 224,000 security personnel. Suppose the cost of training and salaries for one security officer is 5,000 yuan [688 U.S. dollars] per month, the total annual human resource cost for subway security personnel in 2021 would be as high as 13.4 billion yuan [1.8 billion U.S. dollars].

Beijing's three subway operating companies released data for 2022, including security expenses, allowing an estimation of national subway security costs. In 2022, Beijing’s subway security expenses amounted to 1.64 billion yuan [225.7 million U.S. dollars], accounting for a shocking 10.2% of the subway's operating costs. With 1,462 subway entrances in Beijing, if we apply Beijing's standard, the total national subway security expenses in 2022 would be 20.9 billion yuan [2.88 billion U.S. dollars]. However, since Beijing's labor costs are higher than in most other cities, this estimate should be considered the upper bound of national subway security expenses.

The costs considered here only account for the expenses of subway security checks, neglecting the reduced efficiency and convenience they impose on subway travel. This results in additional time costs for citizens during their commutes, an opportunity cost that should be considered in public decision-making. Even without congestion, each passenger spends about 10-30 seconds going through security. During rush hours, the time lost due to security checkpoint congestion can be substantial.

Beijing's three subway operating companies reported a total of 1.233 billion passenger entries in 2022. Furthermore, official data shows that the average daily passenger volume in the first half of 2023 increased by 48.97% compared to 2022. Assuming a 50% increase in total passenger entries for 2023 and an average of 1 minute per passenger to pass through security, this would result in 30 million hours spent on security checks by Beijing subway passengers in 2023.

What is the value of this time? Let's use a common method in public policy analysis of measuring the time cost by wage rates. The average annual salary for employees in Beijing was 178,476 yuan [24,562 U.S. dollars] in 2022. Assuming 250 workdays per year and 8 hours per day, the hourly wage rate can be calculated. Consequently, the time cost for Beijing subway passengers passing through security in 2023 would be 2.677 billion yuan [368.4 million U.S. dollars]. (Note: This calculation estimates the cost of commute time for salaried workers and travel time for others based on the average social wage, making it an upper-bound estimate.)

With such high costs for subway security checks nationwide, what are the benefits? It is naturally assumed that subway security reduces the likelihood of major public safety incidents. However, what is the actual probability of such incidents, and what potential losses could they incur? In July 2019, Beijing Subway reported that since the introduction of security checks in 2008, over 14.97 billion people and 13.77 billion items had been screened, resulting in the confiscation of more than 2.166 million prohibited items. Although the absolute numbers seem significant, the probability of finding prohibited items is less than 0.02%. The main confiscated items included bullets, powderless homemade explosives, handcuffs, spring knives, crossbows, alcohol, and pesticides. The potential safety risks of such items require further scientific evaluation.

Some might argue that subway security deters potential criminal behavior by confiscating prohibited items and filtering out suspicious individuals. While the deterrent effect of subway security is undeniable, there are more cost-effective and efficient deterrent measures than X-ray machines and security gates. In practice, subway security often suffers from low-quality personnel, lack of experience, inconsistent standards, and superficial implementation. From a technological development perspective, China has built the world's largest public video surveillance system, with hundreds of millions of cameras nationwide, creating a strong deterrent to potential criminal activities. Additionally, deploying police officers to patrol key subway stations could have a greater deterrent effect. Given these considerations, could there be a better alternative to routine subway security checks?

Routine subway security checks are just one example. Often, disregard for the costs of safety measures leads to overinvestment in public safety while neglecting the hidden motives behind such investments and their negative socio-economic impacts.

My research team recently investigated local government actions regarding the installation of road cameras. We analyzed over 12,000 procurement notices from the China Government Procurement Network between 2014 and 2019. Using the 2016 reform that replaced business tax with value-added tax as the context, we examined the impact of fiscal shocks on local governments' procurement of road cameras.

We found that financially strapped local governments reduced overall equipment procurement but significantly increased the procurement of road cameras in areas with abundant road resources and higher traffic potential. Procurement in other sectors remained unaffected. This increase aimed to reduce road accidents but also boosted local government revenue from fines, leading to public dissatisfaction, complaints, and a decrease in self-driving tourists.

In early 2024, the State Council issued the "Guidelines for Further Standardizing and Supervising the Setting and Implementation of Fines," addressing the need to "continuously regulate non-contact enforcement" and demanding the cleanup and standardization of electronic surveillance equipment in law enforcement. The guideline emphasizes prohibiting "the arbitrary setup of equipment to increase fine revenues without actual regulatory needs." This indicates that some local governments indeed set up monitoring equipment not for safety but to generate revenue, which undermines the rule of law and business environment, and reduces satisfaction among businesses and the public.

This does not imply that all installations of electronic surveillance equipment have profit-driven motives. In another study, we analyzed the economic impact of public safety video equipment and found that such equipment can deter criminal behavior, enhance residents' sense of security, and promote the development of service industry venues, thereby boosting consumer spending. Therefore, safety and efficiency are not entirely conflicting; safety is the foundation of good property protection, which can stimulate market economic development.

In Oppenheimer, physicist Edward Teller calculated the possibility of a chain reaction from an atomic bomb explosion that could potentially lead to human extinction. Although mathematically small, this probability was not zero, posing a significant risk given the terrifying prospect of human annihilation. Despite this, the United States proceeded with the atomic bomb tests and usage. Often, risks cannot be entirely eliminated; the goal of safety measures should be to reduce risks to a reasonably acceptable level and mitigate worst-case scenarios. Therefore, it is necessary to better understand and evaluate the costs and benefits of various public safety initiatives and analyze their potential negative effects.