## 2 Research Methodology
### Data Collection  
Jobplanet is a job recruitment advertisement and company evaluation-sharing platform that provides information on 95% of companies in Korea employing five or more people. It effectively serves as the Korean equivalent of Glassdoor. The platform has enhanced its review management policies by incorporating the ISO standard on online consumer reviews (ISO20488:2018) [21]. Reviews on Jobplanet are based on users' actual work experiences and are structured into four sections: a company summary review, the company's strengths, the company's weaknesses, and a message to the management. This format offers detailed insights into the specific attributes that contribute to a company's appeal.  
Figure 1: Research Framework. Source: Author’s own work.  
As of February 2025, Jobplanet hosts review information for 90,393 companies. Within its ten industrial categories--service industry, manufacturing/chemicals, healthcare/pharmaceuticals/welfare, distribution/trade/transportation, education, construction, IT/web/telecommunications, media/design, banking/finance, and public institutions/associations--the IT/web/telecommunications sector comprises 12,675 companies.  
The data collection process encompassed text reviews across four distinct categories: titles, advantages, disadvantages, and management suggestions, as illustrated in Figure 2. Each review entry included employee metadata (employment status, posting date, job role) and organizational information (company name, industry classification). In this study, companies with at least five reviews were selected for analysis to prevent bias caused by data scarcity. Of all the reviews on Jobplanet, only those classified under ICT were collected, resulting in an initial dataset of 52,561 reviews spanning May 2019 to August 2020. This enabled analysis of topic evolution throughout the COVID-19 pandemic period. The ICT companies on Jobplanet cover various sectors such as Portal/Internet/Content, E-Commerce, Network/Telecommunications, Hardware, IT Consulting, and Gaming. However, it is important to note that the ICT companies have reviews on Jobplanet.  
This study aims to find out how COVID-19 affects job satisfaction trends. When measuring the effects of COVID-19, using data from a long period of time after the outbreak of COVID-19 has the advantage of utilizing more data, but data from a long period of time after the outbreak of COVID-19 has the disadvantage that the effects of COVID-19 may be weakened. For this reason, [22] used data from before (June and September 2018) and after (June 2020) to assess the effects of pandemic risk on cooperation and social norms, and [23] used data between June 2019 and June 2021 to explore potential factors which influence guests' hotel recommendations before hotels were shut down due to COVID-19 and after they reopened.  
In this study, in order to select a period during which the effects of COVID-19 could be significant, the analysis period was set to be from November 2019 to February 2020, when COVID-19 is believed to have occurred, and the 6 months before and after. Consequently, the final dataset comprised 29,864 reviews from 868 companies, each having five or more employee reviews (Table 1).  
Figure 2: Example of collected review.