A/Prof Harris-Roxas' research activities have focused on primary health care, integrated care, and health impact assessment. His current projects include:

• SEEC
• CHECC
• SHAReD 
• CES-P&CH 
• HIA-IM
• Preventive healthcare for People with Intellectual Disability
• Shisha No Thanks
• Improving access to the hearing services program for people from CALD backgrounds

Some examples of research Ben has led and its impact are described below.

Shisha No Thanks
A/Prof Harris-Roxas led a group of researchers looking at attitudes and beliefs about waterpipe (shisha) use in Arabic-speaking communities. This research led to a Cancer Institute NSW-funded project on raising awareness of the harms of waterpipe use, starting in 2018 and ongoing). This resulted in Ben working community partners and four Health Districts to develop the “Shisha No Thanks” project. As a result of this project a significantly higher proportion of Arabic-speaking young people reported they were aware of the harms of shisha smoking (pre: 45%, post: 68%, p=0.003). This research helped secure an extension of funding, and the project is still ongoing. This research also led to the NSW Ministry of Health and Cancer Institute NSW embedding shisha smoking into broader tobacco control policies and practices. The Shisha No Thanks project won the 2020 South Eastern Sydney Local Health District Healthcare Award in the Keeping People Healthy category and the 2020 Business Campaign of the Year award in the NSW Premier's Multicultural Communications Awards. The UNSW Faculty of Medicine & Health awarded the project the Research Community Engagement Team Award in 2022.

Typology of health impact assessment
Health impact assessment’s (HIA) use has been called for by many international agencies including WHO and the World Bank. Early in the development of the field of HIA, there was debate about the extent to which methods for appraising health risks, quantification models, lived experience, and citizen science should inform assessments. There was also debate about the role government should play in commissioning and undertaking HIAs. In response to this A/Prof Harris-Roxas developed a typology that sets out different forms of HIA, based on an empirical study of the forms of HIA conducted internationally. The typology has been cited more than 150 times and has been used in the national policy and health impact assessment guidance developed in the Republic of Korea, Thailand, and Bhutan. Ben has delivered plenary addresses on the typology at conferences in Dunedin, Seoul, Quebec City, Kobe, and Paris. 

Influencing policy on the use of translation apps in NSW
A/Prof Harris-Roxas and colleagues at UNSW, five NSW Local Health Districts undertook a survey on the use of translation and apps and websites in hospitals and health care settings. The survey of more than 1,500 staff found that a third had used a translation app or website in a clinical encounter, and of those, it was clinicians who initiated use in 66% of cases. These findings led to an update of the NSW Health Policy Directive on Interpreters in to clarify that the use of machine translation is not allowed, and also led to the development of alternatives including the CALD Assist app. 

framework for the impact and effectiveness of health impact assessment
A/Prof Harris-Roxas and colleagues at UNSW developed and piloted a framework for evaluating whether health impact assessments lead to changes to decisions and implementation, which was the first of its kind in the world. This conceptual framework formed the conceptual backbone of a successful ARC Discovery Project. This project remains one of the largest studies that has been conducted internationally on the difference that health impact assessments make to decision-making and implementation. The framework has guided government evaluations in New Zealand and informed a Robert Wood Johnson Foundation-funded review of health impact assessments in the U.S.A. in 2013. Ben was an invited expert for a Pew Charitable Trusts project that evaluated the impact of health impact assessments they had funded in the U.S.A.