## 3 Data and Results
### Results
#### 3.2.2 Efficiency and Technology Change Analysis  
Table 4 shows the results of measuring productivity changes, technological changes, and efficiency changes using 9 companies as panel data from 2013 to 2020, subset data of Table 2. For Malmquist analysis, Stata code was used, and the command is as follows. * malmq price bdywgt = ntwk cpus pcamp sensors btycpcty, ort (out) rts (bcc) period (year) \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Period** & **DMU** & **tfpch** & **effch** & **techch** \\ \hline
1 & 2013–2014 & vivo & 0.997538 & 1 & 0.997538 \\
2 & 2013–2014 & Oppo & 0.994856 & 0.98368 & 1.01136 \\
3 & 2013–2014 & Apple & 1.03269 & 1 & 1.03269 \\
4 & 2013–2014 & Huawei & 0.900117 & 0.98836 & 0.910718 \\
5 & 2013–2014 & LG & 1.17547 & 1.08522 & 1.08316 \\
6 & 2013–2014 & Motorola & 0.907108 & 1 & 0.907108 \\
7 & 2013–2014 & Samsung & 0.851267 & 1 & 0.851267 \\
8 & 2013–2014 & Sony & 1.03092 & 1.02488 & 1.0059 \\
9 & 2013–2014 & Xiaomi & 0.927269 & 1.00003 & 0.927239 \\
10 & 2014–2015 & vivo & 0.954648 & 1 & 0.954648 \\
11 & 2014–2015 & Oppo & 1.04094 & 1 & 1.04094 \\
12 & 2014–2015 & Apple & 1.0053 & 1 & 1.0053 \\
13 & 2014–2015 & Huawei & 0.968941 & 0.99233 & 0.97643 \\
14 & 2014–2015 & LG & 0.923042 & 0.921472 & 1.0017 \\
15 & 2014–2015 & Motorola & 1.12777 & 1 & 1.12777 \\
16 & 2014–2015 & Samsung & 1.33963 & 1.13077 & 1.1847 \\
17 & 2014–2015 & Sony & 0.912589 & 1.04128 & 0.876414 \\
18 & 2014–2015 & Xiaomi & 1.03973 & 1 & 1.03973 \\
19 & 2015–2016 & vivo & 0.891833 & 1 & 0.891833 \\
20 & 2015–2016 & Oppo & 1.09276 & 1 & 1.09276 \\
21 & 2015–2016 & Apple & 1.15064 & 1.14652 & 1.00359 \\
22 & 2015–2016 & Huawei & 0.832492 & 1 & 0.832492 \\
23 & 2015–2016 & LG & 1.03055 & 1 & 1.03055 \\
24 & 2015–2016 & Motorola & 1.03959 & 1 & 1.03959 \\
25 & 2015–2016 & Samsung & 0.845398 & 0.902084 & 0.93716 \\
26 & 2015–2016 & Sony & 0.983122 & 0.947815 & 1.03725 \\
27 & 2015–2016 & Xiaomi & 0.903028 & 1 & 0.903028 \\
28 & 2016–2017 & vivo & 1.11549 & 1 & 1.11549 \\
29 & 2016–2017 & Oppo & 1.01125 & 1 & 1.01125 \\
30 & 2016–2017 & Apple & 0.913949 & 0.872202 & 1.04786 \\
31 & 2016–2017 & Huawei & 1.23524 & 1 & 1.23524 \\
32 & 2016–2017 & LG & 0.823203 & 1 & 0.823203 \\
33 & 2016–2017 & Motorola & 0.959145 & 1 & 0.959145 \\
34 & 2016–2017 & Samsung & 0.989861 & 0.980345 & 1.00971 \\
35 & 2016–2017 & Sony & 0.9785 & 0.940679 & 1.04021 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Results of Malmquist Productivity Analysis. The period is a variable indicating the year for measuring the change in productivity from period t to t + 1. tfpch, effch, and techch are variables corresponding to productivity change, efficiency change, and technological change presented in Equations (6)-(9). The average tfpch for the entire period was 1.0154, the efficiency change was 1.0036, and the technology change was 1.0107. It means that progress has been made in all aspects of total factor productivity, technological change, and efficiency change. Figure 2 examines total factor productivity, technological change, and efficiency change by smartphone maker. In Figure 2a shows the mean efficiency and technology changes for the period of 2013-2020 using Malmquist productivity index and Figure 2b using global Malmquist productivity index. Xiaomi was the fourth company among the sample in the period to lead technological progress and improve productivity while maintaining efficiency. Vivo continued its upward trend after achieving significant technological advances and efficiency gains in 2017 and 2018, with efficiency gains being key prior to 2016. While Sony retains the momentum of technological and efficiency gains it achieved before 2014, overall, it was rated as a productivity, efficiency, and technological setback relative to SOA. Samsung has improved productivity through technological advances while maintaining the status quo in all respects.