Study period	Regional coverage	NTM measure	Methodology	Findings	Reference
1970-2005	Developing, developed, OECD	Imported-related NTMs	Gravity model	Developing countries are negatively affected much by NTMs than developed countries	Carrere et al. (2009)
1991-2002	Developing	SPS	Case study	Some developing countries, such as India, have to close down their plants due to the more stringent standards whilst they had to look for other alternative markets	Mehta and George (2003)
1996-2010	Developing, developed	SPS	The gravity model	SPS measures constitute barriers to agricultural and food trade consistently to all exporters	Pramila and Jasmin (2016)
1996-2013	Developing	SPS, TBT	VARMA(X) and intervention models	NTMs reduce agri-food trade volume in Africa	Liu et al. (2019)
1997-2015	Developing, developed	Imported-related NTMs	The gravity model	NTMs have become an even more dominant source of trade protection	Niu et al. (2018)
1998-2006	Developing, developed	TBT	The modified two-stage gravity model	TBT tends to result in the decline of China’s imports, which are closely linked to the exporting country’s economic development level	Bao (2014)
2001	Developing, developed	SPS, TBT	The gravity model	Environmental-related NTMs used for protectionist causes	Fontagné et al. (2005)
2001-2003	Developing, developed	Imported-related NTBs	The general equilibrium model	The impact of NTBs on trade flows similar to tariffs	Kee et al. (2009)
2001-2006	Developed	Imported-related NTMs	The gravity model and a partial equilibrium model	Negative impacts of NTMs on imports of crustaceans	Disdier and Marette (2010)
2001-2014	China and its trading partners	Imported-related NTMs	The gravity model	Non-technical NTMs are particularly stringent for final goods	Timini and Conesa (2019)
2002-2015	China, Japan, and Korea	SPS, TBT	The inventory approach	From a coverage ratio perspective, Chinese TBT measures reduce Japan and Korea’s manufacturing and total exports as a whole	Wood et al. (2019)
2004	European countries, developing countries and OECD	SPS, TBT	The gravity model and the inventory approach	NTMs significantly reduce developing countries’ exports to OECD countries, and European imports are more negatively influenced by SPS and TBTs than imports of other OECD countries	Disdier et al. (2008)
2010-2012	Developing, developed	SPS, TBT	Market analysis	NTMs used for protectionist causes	Hermelink and Knebel (2012)
2014	Malaysia and its trading partners	Imported-related NTMs	Questionnaire and survey	NTMs, especially technical NTMs, are perceived to be stringent and pose challenges to small and medium firms, resource based firms and firms with less exposure to international markets	Sithamparam, Devadason and Chenayah (2017)
2017	22 papers (16 published in peer-reviewed journals, six from grey literature), 271 observations (point estimates of trade effects of NTMs), and 256 estimated t-statistics	Imported-related NTMs	A meta-analytical approach	NTMs have the trade-impeding effects	Santeramo and Lamonaca (2019)