## 4 Results and Discussion
### Results and Discussions of Attribute Bidirectional Performance  
#### 4.3.1 Results of Attribute Bidirectional Performance  
With the obtained sentiment lexicon, the sentiment values of sub-attributes under each attribute in t-star negative dataset \(D_{t}^{neg}\) and positive \(D_{t}^{pos}\) are respectively obtained by Equations (4)-(10). Each sub-attribute has bidirectional performance, represented by positive sentiment value and negative sentiment value. The top 20 well-performed sub-attributes with the strongest positive sentiment polarity and top 20 poorly performed sub-attributes with the strongest negative sentiment polarity with respect to six attributes in five-star hotel reviews are shown in Tables 7 and 8. The results indicate that the bidirectional performance of the same sub-attributes may affect customer satisfaction differently. For example, considering the sub-attribute \"decorate\" under attribute room, its positive sentiment value from positive reviews is 18,064.37, ranked 3, but on the other hand, the negative sentiment value from negative reviews is \(-\)61.57, ranked 17. That is, for \"decorate\", customers tend to give much more praises when it performs well, whereas customers are probably not sensitive to its poor performance. The observation provides support for the existence of asymmetric relationship between attribute performance and customer satisfaction [24,72]. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Value**} & \multicolumn{2}{c}{**Location**} & \multicolumn{2}{c}{**Service**} \\ \hline
**Sub-Attributes** & **Sentiment Values** & **Sub-Attributes** & **Sentiment Values** & **Sub-Attributes** & **Sentiment Values** \\ \hline quality & 9287.06 & hotel & 127,281.60 & service & 83,160.98 \\ price & 7723.98 & location & 51,065.79 & staff & 77,198.91 \\ value & 7457.58 & great & 47,273.65 & excellent & 19,643.26 \\ overall & 4718.63 & London & 43,130.88 & food & 18,286.84 \\ cheap & 3431.94 & place & 15,842.34 & experience & 17,114.62 \\ money & 3167.76 & perfect & 11,355.46 & quality & 9531.05 \\ rate & 3115.13 & close & 6832.03 & attentive & 8627.21 \\ deal & 2744.77 & station & 6794.12 & superb & 7623.67 \\ compare & 1427.76 & locate & 6678.65 & outstanding & 5455.66 \\ reasonable & 1384.81 & central & 5362.67 & attention & 4843.12 \\ opinion & 874.96 & tube & 5162.28 & exceptional & 3612.60 \\ discount & 441.41 & overall & 5036.61 & deliver & 2642.43 \\ represent & 344.97 & near & 3440.62 & impeccalbe & 1426.53 \\ inexpensive & 282.49 & distance & 3431.87 & exemplary & 1093.08 \\ bargain & 226.16 & heart & 2727.13 & cleanliness & 1029.09 \\ affordable & 176.04 & attraction & 2529.99 & presentation & 415.14 \\ favourably & 169.36 & convenient & 2336.89 & unmatched & 230.21 \\ competitive & 164.94 & boutique & 2066.52 & noteworthy & 157.20 \\ ratio & 73.53 & ideal & 1999.84 & commendable & 155.89 \\ phenomenally & 52.47 & spot & 1966.29 & incomparable & 70.66 \\ \hline \multicolumn{2}{c}{**Room**} & \multicolumn{2}{c}{**Cleanliness**} & \multicolumn{2}{c}{**Sleep Quality**} \\ \hline
**Sub-Attributes** & **Sentiment Values** & **Sub-Attributes** & **Sentiment Values** & **Sub-Attributes** & **Sentiment Values** \\ \hline room & 215,490.83 & room & 112,559.79 & bed & 21,150.78 \\ bed & 20,678.19 & very & 87,177.71 & comfortable & 18,250.67 \\ decorate & 18,064.37 & well & 29,182.25 & sleep & 8989.04 \\ bathroom & 16,396.52 & clean & 26,561.49 & comfy & 2552.32 \\ clean & 13,874.17 & comfortable & 21,693.18 & pillow & 2535.55 \\ suite & 13,413.97 & bed & 20,495.64 & linen & 2019.79 \\ spacious & 9802.36 & nice & 20,308.36 & peaceful & 1063.44 \\ large & 9007.25 & excellent & 18,263.84 & bedding & 1058.61 \\ although & 5901.86 & decorate & 17,812.75 & wake & 913.49 \\ size & 5253.50 & bathroom & 17,204.46 & restful & 606.27 \\ bedroom & 4876.74 & amenity & 15,456.15 & mattress & 499.52 \\ appoint & 4173.68 & modern & 10,517.20 & duvet & 301.12 \\ \hline \hline \end{tabular}
\end{table}