# Overall Equipment Effectiveness: Systematic Literature Review and Overview of Different Approaches
## 3 Results
Instead of for use in production, the new models were built to measure the effectiveness in areas such as transportation, sustainability, mining, electricity and resources (human and monetary). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Application Area**} & \multirow{2}{*}{\begin{tabular}{c} **Inclusion** \\ **Criteria** \\ \end{tabular} } & \multirow{2}{*}{**1996-2000**} & \multirow{2}{*}{**2001-2005**} & \multirow{2}{*}{**2006–2010**} & \multirow{2}{*}{**2011-2015**} & \multirow{2}{*}{**2016-2020**} \\ \cline{1-1} \cline{5-7}  & I1 & & [28; 29; 30] & [31; 32] & [33; 34; 35; 36; 37; 38; 39] & [26; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 60; 62; 69; 61; 63; 62; 64; 65; 66; 67; 68; 69; 62; 63; 68; 69; 64; 65; 66; 67; 68; 69; 66; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84; 85; 86; 87; 88; 89; 90; 91; 92; 93; 94; 95; 96; 97; 98; 99; 100; 101; 102; 103; 104; 105; 106; 107; 108; 109; 111; 112; 113; 114; 115; 116; 117; 118; 119; 120; 121; 122; 123; 124; 125; 126; 127; 128; 129] & [130; 131; 132; 133; 134; 135; 136; 137; 138; 139; 140; 141; 142; 143] \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Productivity in \\ manufacturing processes \\ \end{tabular} } & I1 & & [150; 151; 152] \\ \cline{2-5}  & I3 & & & [153] \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Productivity in \\ maintenance \\ \end{tabular} } & I1 & [9] & [157] & [158, 159] & [160; 161; 162; 163; 164; 165; 166] \\ \cline{2-5}  & I3 & & [167] & [168] & [169] & [170; 171; 172] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Overall equipment effectiveness (OEE) application contribution by area. Figure 3: **The** effort in terms of (**a**) geographical location (**b**) top 10 country production and (**c**) authors contribution over the time. Two types of keywords are shown in Table 2: the author's keywords and keywords plus. The former is provided by the original authors, whereas the latter is extracted from titles of cited references by Clarivate Analytics (WoS). Figure 5 shows the co-occurrence network of the author's keywords; the number of nodes in the network was 40 and was related through association; the clustering algorithm used was Louvain. The network comprised four clusters. The first one comprised nine keywords related to the OEE formulation, availability, performance, quality, downtime, speed loss, etc. The second cluster comprised 12 keywords related to total productive maintenance, optimization, production, maintenance and autonomous maintenance. The third cluster comprised terms such as effectiveness, throughput and performance measurement. The last cluster comprised 13 keywords pertaining to current issues, such as Industry 4.0, simulation, lean manufacturing, six sigma, SMED and DMAIC. Initially, studies regarding OEE are associated with total productive maintenance; subsequently, they are associated with the industry, availability and manufacturing process. Currently, they are related with terms such as lean manufacturing, improvement, implementation, reliability, design and optimization. The most cited document obtained from the systematic review considers quality assessments, such as lean tools and six sigma, to improve productivity and financial savings, e.g., in the die-casting unit of a company [115]. Figure 4: Distribution of inclusion criteria of analysis. Figure 5: Co-occurrence network. RQ (2). What models based on OEE have been developed? Over time, industries have adapted OEE to their needs. Hence, several authors have developed slight modifications to [PERSON]'s model whereas others have developed new indicators based on the originally formulated OEE. A list of models based on OEE, listed by the author and model name, is shown in Table 4. A brief description of each model is provided as well.