New research has shown that cashiers would need higher wages for handling cash, as compared to card, to compensate for the stress of counting the wrong sum. This trade-off between wages and stress has implications for future job design.

The research by the National University of Singapore (NUS) Business School was published in the peer-reviewed journal Service Science in July 2021.

“Cashiers are often asked to top up the shortfall from their own pocket if there is a discrepancy between the value of goods sold and the sum in the cash register. This can lead to stress,” said lead author Professor Ivan Png from the Department of Strategy and Policy at NUS Business School. He added, “We wanted to find out if there is an extra cost for cashiers’ willingness to take on this stress.”

Professor Png conducted the research with former NUS Business School research fellow Charmaine Tan, who is now with the Institute of High Performance Computing at the Agency for Science, Technology and Research (A*STAR).

In the duo’s earlier study in the publication Macroeconomic Review, they had found that the preference for cash varied widely across countries, partly due to different levels of privacy concerns and trust in banks. Prof Png, who also teaches Economics at the NUS Faculty of Arts and Social Sciences, observed, “People are using more cashless payments during the pandemic, but old habits die hard. Many people still use cash for small-value transactions.”

The persistence of cash usage motivated them to investigate how payment modes affect cashiers’ willingness to work.

Higher cashier wages in regions where cash usage was high

The new research consisted of three studies. The first study looked at cashier wages across countries to see if they require extra wages to handle payments in cash, compared to payments by cards. The researchers analysed data on cash usage and cashiers’ wages from 20 countries and regions, including Australia, South Korea and the United States, over the period 2009 to 2019. The findings suggested that in countries where cash payments were more frequent, the wages of cashiers were also higher. This implied that cashiers required a wage premium for handling cash.

Cashiers willing to handle cash for additional S$1.50 per working day

To find out this wage premium, the researchers surveyed over 100 cashiers from 15 outlets of a supermarket chain in Singapore. In this second study, the cashiers were asked if they preferred to handle card payments at their current monthly salary or preferred to collect payment by cash and earn S$X more per month.

With no wage premium, 79 per cent of the 112 cashiers preferred to handle card payment. A minority, 5 per cent, preferred cash payment and the rest, 16 per cent, were indifferent. The researchers also found that for those who preferred cash, the median wage premium for accepting cash was $37.50 per month. This was about 1.8 per cent of a cashier’s monthly wage of $2,100. This meant that the median cashier was willing to switch from the task of handling payment by card to one by cash for an additional S$1.50 per working day. They also found that the wage premium for handling cash was lower among cashiers who are local, less risk averse, and younger.

More stress for high earners handling cash

The researchers also investigated the role of stress in explaining the wage differential for handling cash. This was carried out in a third study with 122 vocational students studying retailing, cashiering, customer service, and sales, using an electrocardiogram (ECG) device in a laboratory setting. The researchers measured stress using the participants’ heart beat-to-beat intervals as an indicator.

Earning a small sum for each correct transaction in 15 minutes, the participants were randomly assigned, without being informed, to the high-cash condition, where 70 per cent of the payments were made in cash; or the low-cash condition, where 70 per cent of the payments were paid by card.

The researchers found that in the high-cash condition, high earners showed more stress than low earners. However, this difference was not seen in the low-cash condition. High earners also scored higher in arithmetic and were more risk averse.

Professor Png said, “Our results showed that job design affects workers’ willingness to work. They are willing to accept lower wages for tasks with less stress. When we design jobs that improve workers’ welfare, perhaps using automation, there is direct savings in labour costs, since engaged and satisfied workers require lower wages. When we have happy workers attending to customers, you are likely to get happy customers too.”

For their next steps, the researchers aim to study the effect of technologies on cashiers when the collection of payment is automated.


For media enquiries, please contact:

ANG Hui Min
Acting Head, Corporate Communications
NUS Business School
National University of Singapore
Tel: +65 6601 5857
Email: [email protected]


About National University of Singapore (NUS)

The National University of Singapore (NUS) is Singapore’s flagship university, which offers a global approach to education, research and entrepreneurship, with a focus on Asian perspectives and expertise. We have 17 faculties across three campuses in Singapore, with more than 40,000 students from 100 countries enriching our vibrant and diverse campus community. We have also established our NUS Overseas Colleges programme in more than 15 cities around the world.

Our multidisciplinary and real-world approach to education, research and entrepreneurship enables us to work closely with industry, governments and academia to address crucial and complex issues relevant to Asia and the world. Researchers in our faculties, 30 university-level research institutes, research centres of excellence and corporate labs focus on themes that include energy; environmental and urban sustainability; treatment and prevention of diseases; active ageing; advanced materials; risk management and resilience of financial systems; Asian studies; and Smart Nation capabilities such as artificial intelligence, data science, operations research and cybersecurity.

For more information on NUS, please visit

About NUS Business School

The National University of Singapore (NUS) Business School is known for providing management thought leadership from an Asian perspective, enabling its students and corporate partners to leverage global knowledge and Asian insights.

The school has consistently received top rankings in the Asia-Pacific region by independent publications and agencies, such as The Financial Times, Economist Intelligence Unit, and QS Top MBA, in recognition of the quality of its programmes, faculty research and graduates.

The school is accredited by AACSB International (Association to Advance Collegiate Schools of Business) and EQUIS (European Quality Improvement System), endorsements that the school has met the highest standards for business education. The school is also a member of the GMA (Graduate Management Admission) Council, Executive MBA Council, Partnership in Management (PIM) and CEMS (Community of European Management Schools).

For more information, please visit, or go to the BIZBeat portal, which showcases the School’s research.HJKL

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