Sentiment analysis: Quantifying customer satisfaction in Korean cuisine
This project synthesizes real-life Yelp customer reviews from various Korean restaurants into one representative model. Prepared for the Chief Operating Officer (COO), this report provides an in-depth analysis of these reviews to figure out what areas should be improved and how to increase the star rating.
Natural Language Processing (NLP) is utilized to go through each review and check which categories get mentioned (ambience, cleanliness, food, price, service). After that sentiment is assigned for those categories (positive, neutral, negative). If a category is not mentioned in the review, the category is simply left blank. Overall sentiment is also provided for all reviews, but this field is not used in the final report. Star rating from 1-5 already existed on these reviews.
In-depth analysis is based on yearly/quarterly data between January 2023 – December 2025. The key insights and recommendations focus on the following areas and questions:
- Which categories influence low star ratings (1-2) and negative sentiment?
- Which categories are talked about often among low star ratings?
- How should categories be prioritized from most important to least important and why?
Data structure overview
The final data table structure is visualized below with some examples of feedback with categories and sentiment.
Executive summary
Overview & methodology
- This section uses “Net Sentiment Score (NSS)” table and "Mention frequency" line charts for 1- and 2-star reviews.
- NSS measures the balance of customer sentiment, ranging from +100 (all positive) to -100 (all negative).
- NSS does NOT take neutral sentiments into account. For deeper analysis, see the “Insights deep dive” segment.
- Mention frequency indicates how often category is mentioned out of all 1- and 2-star reviews by percentage.
Priority ranking & key drivers
Service (top priority):- Among 1-star reviews service is a big driver for negative sentiment, almost being all negative in some time periods. it's also the most mentioned category between 2024 Q4 – 2025 Q3.
- Among 2-star reviews there is volatility on how often service is discussed, but overall, it's still the second most mentioned category with plenty of negative sentiment.
- When service fails, it's the primary driver of lowest ratings.
- Overall, the most discussed category.
- Since food is a common topic with negative sentiment, it's considered 2nd priority.
- Food is slightly below service, because it's not as much of a negative driver.
Price (3rd priority):
- Sentiment is mostly negative and overall, it's the 3rd most discussed category.
- Data suggests that some customers feel the experience (service + food) does not justify the cost.
- Although price is a big driver for negative sentiment, it's discussed way less than food and service, making it a slightly lower priority.
- Sentiment is almost all negative among 1-star reviews and in 2025 among 2-star reviews.
- Least discussed category among 2-star reviews but it's discussed more among 1-star reviews.
- For reasons above it's the 4th priority.
- Sometimes the least discussed topic among 1-star reviews.
- It has negative sentiment, especially among 1-star reviews.
- Ambience is the last priority but that doesn’t mean it’s not important.
Insights deep dive
This segment uses stacked area charts to visualize sentiment distribution (positive, neutral, negative) and line charts to track mention frequency across 1-star, 2-star and all reviews.
Service: The primary detractor (top priority)
- Among all reviews there is volatility of negative sentiment.
- Negative sentiment reached its second highest peak in 2023 Q4 (27,39%) and highest in 2025 Q3 (29,85%).
- Between these peaks negative sentiment went down. At its lowest it was 16,74% in 2024 Q2.
- Service is almost all negative among 1-star reviews.
- This is especially true in 2024 and first half of 2023.
- During 2025 negative sentiment started to go down with some positive and neutral sentiment increasing instead.
- Service is a common topic with plenty of negative sentiment, making it the top priority.
- Overall, the second most mentioned category.
- Between 2024 Q4 – 2025 Q3 among 1-star reviews it was the most mentioned category.
Food: High engagement, secondary risk (2nd priority)
- Food has the most positive sentiment and it's the most discussed category.
- Among all reviews negative sentiment remains below 20% during the timeline.
- Among all reviews food is mentioned over 90% during the timeline. Same tracks with 2-star reviews.
- However, among 1-star reviews discussion goes down. In 2024 Q2 food was mentioned 94,83% but after that it goes down below 80% for the rest of the timeline.
- Since food is overall the most discussed category with good amount of negative sentiment, it’s considered the second priority.
- Among 1- and 2-star reviews, after 2024 Q2 negative sentiment started to go down.
- However, among all reviews negative sentiment started to increase from 2025 Q1 until 2025 Q3. In 2025 Q4 negative sentiment was at 15,22%.
- Food is the second priority, because it’s not as much of a driver for low ratings compared to service.
Price: Declining value (3rd priority)
- Among all reviews negative sentiment has been increasing since 2024 Q3.
- In 2025 Q4 positive sentiment is below 50%.
- While many love food and service, some think it’s not worth the price.
- Sentiment is almost all negative among 1- and 2-star reviews.
- Compared to all reviews, mentions also increase among low star ratings.
- However, prices are still discussed way less compared to service.
- Price can become a higher priority if these trends keep persisting.
- Right now, price is slightly lower priority below food because it's not nearly as big of a topic.
- Since 2025 Q3 mentions started to increase, especially among 1-star reviews. Also, since negative sentiment is increasing among all reviews, prices can become a second priority in 2026.
Cleanliness: The “polarizing” category (4th priority)
- People either love it or hate it. Cleanliness has minimal neutral sentiment.
- Among 1-star reviews it's almost all negative sentiment.
- Data is very volatile among 2-star reviews. However, it's almost all negative in 2025.
- Among all reviews in 2023 Q3 negative sentiment was at 40,99% but it went down after that consistently to 19,30% in 2025 Q1. However, negative sentiment increased after that and in 2025 Q3 it was at 44,88%.
- Since overall cleanliness is the least discussed category, it’s considered 4th priority.
- Among 1-star reviews in 2024 cleanliness is sometimes discussed more often than ambience.
- Cleanliness is above ambience, because it’s considered a bigger driver for negative sentiment.
Ambience: The neutral category (last priority)
- Ambience has the greatest number of neutral reviews.
- Among all reviews sentiment is slightly more neutral than negative.
- Data has a lot of volatility among 1- and 2-star reviews with different sentiments. Overall, it’s still mostly negative.
- Considered a last priority for its neutral nature and sometimes being the least discussed category.
- Among 1- and 2-star reviews mentions go down compared to all reviews.
- Ambience is still an important category. Especially since neutral and negative sentiment is increasing in 2025 among all reviews.
Recommendations
Based on the insights, here are recommendations for the restaurant.
Service:- Address the volatility of negative sentiment with the staff. What did they do differently when negative sentiment was going down in 2024 but went back up again in 2025?
- Train the staff to resolve issues when guests seem unhappy e.g. offering a free drink.
- Increase staffing levels during peak hours to ensure quality does not drop when the restaurant is full.
- Since negative sentiment increased in 2025, conduct a menu audit to ensure recipe consistency across all shifts.
- Capitalize on positive sentiment and the fact that it’s the most discussed category. Highlight "fan favorite" dishes in marketing to maintain their status as a primary draw.
- Introduce lunch specials or "family sets" that increase the perceived value of the meal.
- Evaluate if portion sizes have decreased over the timeline.
- Like with service, address the volatility of negative sentiment between 2023 Q3 – 2025 Q3 with the staff.
- Focus on first impressions by making sure the entryway and common areas are spotless to prevent immediate negative bias.
- Implement an hourly restroom and dining area checklist to eliminate these "deal-breaker" negative experiences.
- Ambience should be addressed only after service and food scores have stabilized.
- Address negative/neutral sentiment by reviewing things like lighting and music volume.
- Since this is the lowest priority, avoid major renovations and focus on small updates.