## 4 Discussion and Conclusions  
This study aims to examine the efficiency of Vietnamese ICT companies not only in the past period (2013-2017) but also in future periods. To do this, we applied Grey model to obtain forecasted data for period 2018-2022, and then employed the DEA approach to measure performance efficiency and efficiency improvement of 24 sample ICT companies over 2013-2022. Firstly, DEA-super SBM was applied to obtain the score and ranking of all ICT companies in Vietnam over the past period 2013-2017. The obtained results indicated half of selected ICT companies were inefficient and the distance from the lowest average score to the highest average score is notable, which indicates an extreme difference in controlling the inputs and outputs of these companies as well as the high competitiveness in the ICT industry in Vietnam. Secondly, the Grey model was applied to forecast the value of inputs and outputs for the future period 2018-2022. After testing the accuracy of prediction, all the forecasted data were used to evaluate the performance of these ICT companies during 2018-2022 under Super-SBM model. The findings revealed that more than half of ICT companies would operate ineffectively and perform poorly in terms of efficiency. Additionally, the number of efficient companies will also be significantly reduced. However, despite the decrease in the number of efficient firms, the average efficiency score over period 2018-2022 will still be higher than the score of the past period 2013-2017, driven by the much better performance of one company (DMU10). The distance between the efficient one and inefficient DMU will be larger, which raises alert to the companies poorly performing in the industry. Figure 1: Average mean of MPI change of information and communication technology (ICT) industry. The Malmquist Productivity Index was employed in the next step to examine efficiency improvement. The Malmquist model's results provide insight views into the ICT industry in terms of \"efficiency changes\", \"technological changes\", and MPI. Generally, these results provide an insight view of past and future performance of ICT companies. Findings of this study reveals that the ICT industry of Vietnam always has a positive change over 2013-2022. By comparing the industry average with the results of each business, it is possible to help in recognizing the weakness as well as strength of the ICT industry, which help to make suitable strategies. Results indicators show that the ICT industry in Vietnam in general has always been effective over the years, which strongly confirm that the ICT industry is worth the investment. However, individual examining the performance of each company, the results reveals that the number of inefficient companies in each year is always higher than efficient ones. This result implies that the industry will have much more potential for growth if it is possible to improve the number of efficient businesses. By comparing the industry average with the results of each business, helping businesses to realize where they are in the market, recognizing the inefficiencies of businesses also help to provide an option for investors. Investors can use this approach to discover good companies for investments. This mathematical approach reduces the errors and risks in decision-making. This research also demonstrates that the proposed approach can help decision-makers and policymakers to develop strategies for sustaining the development of the Information and Communication Technology industry. According to forecasted MPI, companies with inefficient level (\(<1\)) need to be positive in changing or improving their management activities, business trends or size, or any other methods to make progress in the future time. Additionally, by showing an industry average performance index that is always greater than 1, it shows that the potential for investment is profitable.