Sample and scope

This section explains the similarities and differences of the samples and scope of the reviewed studies. The differences in the following characteristics of the sample of the earlier studies can partially explain the difference in their findings.

2.3.1.1. Size of the sample

There is a significant difference between the sizes of the samples in the reviewed studies. As shown in table 2-9, Lee & Lee’s (2015) study is based on nine firms and the Durate et al. (2011) study is based on 1200 firms. Overall, fifteen of the analysed studies incorporated fewer than 100 companies in their samples and twelve studies more than 300 companies. The remainder of the studies used a sample of between 100 and 300 companies. Since most of the statistical analysis methods are sensitive to sample size, as Lakhal et al. (2006) have argued, using a larger sample size will give more reliable results and increase the generalisability of the findings.

2.3.1.2. Countries

Three of the reviewed studies are based on a mixture of different countries. For example, the studies by Rosenzweig et al. (2003) and Yang et al. (2011) are based on thirty-five and twenty-two different countries respectively. However, as shown in table 2-9, most of the reviewed studies are based on US companies (fourteen studies). The others are based on fifteen different countries. Some of these studies, such as Abusa & Gibson (2013) and Wang et al. (2014), argue that their findings are only applicable to the countries where their studies were conducted. Therefore, it is not clear if the relationship between operational practices and financial results are context-specific or, as identified by Rosenzweig et al. (2003) and Yang et al. (2011), there are similarities between different countries. Comparative studies using data from different countries can clarify this ambiguity.

2.3.1.3. Size of the companies incorporated in the sample

Most of the studies have incorporated a mixture of SMEs and large companies in their sample (twenty-five studies). As shown in table 2-9, three studies were only based on SMEs, one study is only based on medium-sized companies (i.e. Dubey et al., 2014) and one only based on large firms (i.e. Zhang, 2005). The other studies have not stated the size of the companies incorporated in their samples. However, although most of the reviewed studies use a mixture of SMEs and large companies, they suggest one set of findings for all companies regardless of their size. However, as argued by Jin (2006) and Dubey & Gunasekaran (2015), the size of the firms is influential in the relationship between operational practices and financial results. Therefore, there is the need to study the difference between SMEs and large companies in the way

2.3.1.4. Industry sector of companies incorporated in the sample

As shown in table 2-9 most of the studies are either only based on the manufacturing companies or a mixture of manufacturing and service companies. However, there are two studies based solely on the financial service sector, one based on retailer and one based on a service industry. The other studies have not stated the industry sectors of their samples. Some of these studies, such as Fotopoulos & Psomas (2010) and Valmohammadi (2011), claim that their findings are only applicable to the industry sectors that they have employed in their samples. Therefore, there is a need to study how companies that work in different industry sectors vary in the way their operational practices affect their financial performance.

Table 2-9 Sample and scope of the reviewed studies

# Author(s)/Date _{the sample}Size of Country Size of the companiesincorporated in the sample

Industry sector of companies incorporated in the sample 1 Ittner & Larcker (1998) 1 service provider_{(73 branches)} USA Not specified Financial service 2 Callen et al. (2000) 100 firms Canada Medium & large Manufacturing 3 Fullerton & McWatters (2001) 95 firms USA SMEs & large Manufacturing 4 Nilsson et al. (2001) 482 firms Sweden Medium & large Manufacturing & Service 5 Fullerton et al. (2003) 253 firms USA Not specified Manufacturing 6 Kaynak (2003) 382 firms USA SMEs & large Manufacturing & Service 7 Rosenzweig et al. (2003) 238 firms Mixture of 35_countries SMEs & large Manufacturing 8 Yasin et al. (2004) 68 firms Portugal SMEs & large Manufacturing 9 Hertenstein et al. (2005) 68 firms USA Not specified Manufacturing 10 Kannan & Tan (2005) 565 firms Mixture of_countries SMEs & large Not specified 11 Zhang (2005) 153 firms USA Only large Manufacturing & Service 12 Jin (2006) 113 firms USA SMEs & large Manufacturing 13 Lakhal et al. (2006) 92 firms Tunisia Medium & large Manufacturing 14 Banker & Mashruwala (2007) 1 retailer (800_stores) USA Not specified Retailer 15 Han et al. (2007) 441 firms USA Not specified Manufacturing 16 Sila (2007) 286 firms USA SMEs & large Manufacturing & Service 17 Huang et al. (2008) 83 firms Taiwan Medium & large Manufacturing 18 Jayaram et al. (2008) 57 firms USA Not specified Manufacturing 19 Ngo et al. (2008) 600 firms China SMEs & large Manufacturing 20 Fullerton & Wempe (2009) 121 firms USA SMEs & large Manufacturing 21 Kumar et al. (2009) 14 firms Canada Medium & large Manufacturing 22 Lee et al. (2009) 698 firms Korea Only Small firms Manufacturing & Service 23 Liu & Barrar (2009) 355 firms UK SMEs & large Manufacturing 24 Fotopoulos & Psomas (2010) 370 firms Greece Mainly SMEs (84 %) Manufacturing & Service 25 Li et al (2010) 607 firms China SMEs & large Not specified 26 Crisostomo et al. (2011) 78 firms Brazil Not specified Manufacturing & Service 27 Durate et al. (2011) 1200 firms Brazil Medium & large Manufacturing 28 Valmohammadi (2011) 53 firms Iran Only SMEs Manufacturing 29 Yang et al. (2011) 309 firms Mixture of 22_countries SMEs & large Manufacturing 30 Agus & Hajinoor (2012) 200 firms Malaysia SMEs & large Manufacturing

# Author(s)/Date _{the sample}Size of Country Size of the companiesincorporated in the sample

Industry sector of companies incorporated in the sample 31 Duh et al. (2012) 209 firms Taiwan SMEs & large Manufacturing

32 Hofer et al. (2012) 229 firms USA SMEs & large Manufacturing 33 Lee & Roh (2012) 230 firms USA SMEs & large Manufacturing & Service 34 Tarigan & Widjaja (2012) 55 restaurants_{and cafés} Indonesia Not specified Service Industry 35 Abusa & Gibson (2013) 56 firms Libya SMEs & large Manufacturing 36 Dubey et al. (2014) 100 firms India Only medium-sized_firms Manufacturing 37 Lakhal (2014) 176 firms Tunisia Not specified Manufacturing & Service 38 Wang et al. (2014) 228 firms China SMEs & large Not specified

39 Dubey & Gunasekaran (2015) 132 firms India SMEs & large Manufacturing & Service 40 Lee & Lee (2015) 9 firms Taiwan Not specified Financial (Insurance)

In the next section, the time horizons, the methods of selecting variables and data collection, and data analysis methods employed in the earlier studies are discussed.