In this section, we firstly analyze the benchmark case where the monopolistic firm and consumers make decision without misrepresentation and then examine the misrepresentation case where the monopolistic firm and consumers make decisions with misrepresentation. Finally, we investigate the effect of misrepresentation on the monopolistic firm and consumers. To distinguish the two cases, we adopt different superscriptions and to describe the benchmark case and the misrepresentation case.
4.1. Firm’s Personalized Service Efforts and Consumers’ Purchasing Behaviour without Misrepresentation
We firstly analyze the case that consumers do not misrepresent, that is, all of the personal information the firm collected is consumers’ privacy information (). With backward induction, we firstly derive the expected demand in the market.
Consumers buy from the firm if their utility is not less than zero, that is,
. Hence, the expected demand in the market is given as follows:
In Equation (3), all consumers in the market will buy from the firm when the personalized service level is greater than . Otherwise, only part of consumers whose perceived utility is greater than zero buys from the firm.
Following the upper-mentioned timing sequence, with backward induction, the monopolistic firm sets her personalized service level to maximize her expected profit. We substitute Equation (3) into Equation (2), with F.O.C, we can derive the equilibrium solutions as follows.
Proposition 1.
If consumers do not misrepresent, the monopolistic firm’s optimal personalized service level is , correspondingly, the expected demand and expected profit of the monopolistic firm are
Proposition 1 shows the monopolistic firm’s optimal personalized service level, expected demand and profit when consumers don’t misrepresent. As in Equation (3), if the firm provides personalized service level is not less than , all consumers will buy from the firm, hence the expected demand equals to 1. If the firm provides her personalized service level greater than 1, her expected profit will decrease, hence, the optimal personalized service level is when all consumers buy from the firm. When the firm offers personalized service level is less than , some of the consumers will choose not to buy, the expected profit may decrease. With a given personalized service level, the expected demand equals to , with F.O.C of the firm’s profit function, we derive the optimal personalized service level is .
The intuition is as follows. When the unit cost of personalized service level is low, it means that the marginal expected profit is great, offering a greater personalized service level can help the firm to cover the whole market and get more profit. But when the unit cost of personalized service level is high, the marginal excepted profit decreases. To maximize her excepted profit, the firm need to decrease her service level, and only some of the consumers will buy from the firm.
Hence, the monopolistic firms should choose her personalized service level strategy depending on the unit cost of the unit cost of personalized service. When the unit cost of personalized service is low, she should set a personalized service level equals to and covers the whole market. Otherwise, she should decrease her personalized service level to maximize her expected profit, which results to the scenario where only part of consumers are covered with the firms’ personalized service.
Corollary 1 is derived from Proposition 1 and summarizes how the product price, unit value of consumer’s privacy information and the unit cost of personalized service impact on the firm’s optimal personalized service level, demand and expected profit. To make the expression in the rest of the paper clearer, we define that if , the market is fully covered; otherwise, the market is partly covered.
Corollary 1. If consumers do not misrepresent,
(1) When the market is fully covered, (i) ; (ii) if , ; if , ; if , when , , otherwise, .
(2) When the market is partly covered, (i) ; (ii) if , , otherwise, ; (iii) if , ; if , when , , otherwise, ; if , .
Corollary 1 shows how the relationship between the product price and the firm’s optimal personalized service level, demand and expected profit. It is clear that an increasing product price encourages the firm to provide greater personalized service level under two cases. Because the firm can get more marginal profit with greater personalized service level. But the relationship between the product price and the demand and the expected profit varies with parameter and in the two different cases. In Corollary 1 (1), it is interesting that when the market is fully covered, a greater product price may decrease the firm’s expected profit even the unit value of consumer privacy information is high. When the unit value of consumer privacy information is low, no matter the unit cost of personalized service changes, the expected profit always decreases in price. Because when is low, it means the expected additional profit is low, but the cost of personalized service increases, it leads to a decreasing marginal profit, hence, the expected profit decreases in price. Similarly, when , the marginal expected profit decreases with the increasing price. But when , it represents that the unit value of consumer privacy information is high, meanwhile the unit cost of personalized service is low, if the product price is lower than , the expected profit increases in , because in this scenario, the marginal expected profit increases with and always greater than zero, the firm always gets more profit with an increasing product price. But if the product price is greater than , the personalized service cost increases which decreases the marginal expected profit and the marginal expected profit is always less than zero.
When the market is partly covered, the increasing product price impacts on the expected demand differently. When the unit cost of personalized service is high (), the marginal expected profit is always less than zero, and decreases with an increasing product price. To maximize her profit, the firm should reduce her personalized service level until the marginal expected profit equals to zero. A lower personalized service level leads to a less demand. Oppositely, when the unit cost of personalized service is low (), the firm should increase her personalized service level to cover more consumers until the marginal expected profit equals to zero. When the firm increases her personalized service level, the expected demand increases. Similar with the analysis in the case where all consumers are covered, we can derive the relationship between the product price and the expected profit. But in Corollary 1, when the unit cost of personalized service is in the middle range (), the expected profit firstly increases and then decreases in the product price, and the trend is different with the trend of the demand. That is, if , the firm gets more demand but less profit with an increasing product price. The reason is an increasing increases the firm’s personalized service level, but increases the cost of personalized service, when , the marginal expected profit is less than zero and decreases in .
Corollary 1 indicates that if the firm increases her product price, she should provide higher personalized service level correspondingly. Meanwhile, the firm should not increase her product price blindly, only in the scenario where the unit value of consumer privacy information is high and the unit cost of personalized service is low, an increasing product price can help her to get more profit.
Based on Proposition 1, we can derive the following corollary.
Corollary 2. If consumers do not misrepresent,
(1) When the market is fully covered, (i) ; . (ii); .
(2) When the market is partly covered, (i) ; ; if , ; if , when , , when , . (ii), , .
In Corollary 2(1), the firm set her personalized service level only depending on the product price and cover the whole market. Based on the consumer ’s utility function, the additional profit of consumer’s privacy information and the cost of personalized service are unrelative. Meanwhile, since the product price is given, the increasing unit value only increases the additional expected profit of the firm, and the increasing unit cost of personalized service only increases the cost of the firm.
But in the case that only part of the market is covered, an increasing unit value of consumer privacy information may reduce the firm’s expected profit when the unit value of consumer privacy information is low and the unit cost of personalized service is high. The explanation is as follows, an increasing unit value of consumer privacy information increases the personalized service level and the potential demand, but it increases the cost simultaneously. As a result, the marginal expected profit decreases and is less than zero. Hence, the expected profit decreases in the unit value of consumer privacy information.
Corollary 2 suggests that if the firm can cover the whole market, she should try her best to fully explore the value of consumer privacy information. But if she only covers the market partly, she should be cautious to explore the value of consumer privacy information. Especially, when the unit cost of personalized service is high, but the unit value of consumer privacy information is relatively low, the firm should not try to explore the value of consumer privacy information.
4.2. Firm’s Personalized Service Efforts and Consumers’ Purchasing Behaviour under Misrepresentation
In this section, we assume that consumers will misrepresent when they perceive the privacy risk when their personal information are collected by the monopolistic firm. Following the timing sequence in
Section 3, with backward induction, we firstly derive the optimal proportion of privacy information. Consumers try to maximize their utilities as far as possible based on Equation 1, with F.O.C, we can derive the response function of optimal proportion of privacy information is:
Equation 4 shows that when the monopolistic firm provides a greater personalized service level, consumers will disclose more privacy information. Intuitively, it is a win-win game, the firm provides a greater personalized service level which encourages consumers disclose more privacy information; meanwhile, when consumers disclose more privacy information which will help the firm to provide a greater personalized service level.
Similar with the analysis in
Section 4.1, consumer
buy the firm’s product if
. Since the maximized potential demand is 1, we separate our analysis into two parts, one is the market is fully covered, the other is the market is partly covered. When the market if fully covered, consumer
’s minimized utility function is
When the market is partly covered, consumer
’s utility function is given as Equation (1), consumers whose utility satisfies
buy from the firm. Hence, we can derive the expected demand function as follows.
In Equation (6), if the personalized service level is greater than , all consumers in the market will buy from the firm, otherwise, only part of consumers buy from the firm and the expected demand increases in the firm’s personalized service level. Combining Equation (2) and Equation (6), with F.O.C, we can derive the equilibrium solutions when consumers misrepresent as follows.
Proposition 2.
If consumers misrepresent, the monopolistic firm’s optimal personalized service level is , correspondingly, the expected demand and expected profit of the monopolistic firm are
, where , .
Proposition 2 shows the monopolistic firm’s optimal personalized service level, expected demand and profit when consumers misrepresent. Following the timing sequence in
Section 3, consumers make their misrepresentation decisions depending on the firm’s service level. Intuitively, the firm should increase their personalized service level to encourage consumers to provide more privacy information until she captures all consumers in the market. But providing personalized service is costly, a higher personalized service level increases the cost and may decrease the expected profit, so the firm may choose a different personalized service strategy to maximize her expected profit when the unit cost of personalized service is high.
Proposition 2 also shows that even the firm captures all consumers in the market, she is still driven to choose a higher personalized service level when the unit cost of personalized service is less than . The reason is a low unit cost of personalized service decreases the marginal cost and increases the firm’s marginal expected profit. Hence, even the firm captures all the consumers in the market, she should increase her personalized service level when the unit cost of personalized service is low.
Corollary 3. If consumers misrepresent,
(1) When the market is fully covered, (i) when , ; otherwise, . (ii) when , if , , otherwise, .
(2) When the market is partly covered, (i) when , ; otherwise, .
Corollary 3 shows the relationship between the firm’s optimal strategies and her price. In Corollary 3(a), the market is fully covered. When the unit cost of personalized service is low, if the monopolistic firm increases her price, she wouldn’t increase her personalized service level simultaneously. Because when the unit cost of personalized service is low, the monopolistic firm captures all consumers in the market when she offers a service level equals to , even she increases the price, consumers don’t misrepresent more, so she won’t increase her service level. But when the unit cost of personalized service is high, she should increase the price to maintain the marginal profit. But the relationship between the firm’s profit and price is different. Corollary 3(a) indicates when the firm increases her price, even she increases her service level which increases her cost, she may get more profit. In Corollary 3(a), in the scenario where the unit value of consumer privacy information is low and the price is high, an increasing price may reduce the firm’s profit, because in this scenario, the firm should provide a greater service level to attract consumers, but consumers will misrepresent more which reduce the firm’s additional profit. Hence, in practice, the firm should avoid to increase her price in this scenario, or she should explore the value of consumer information.
In Corollary 3(b), the market is partly covered, when the unit cost of personalized service is high. When the unit cost of personalized service is low, the monopolistic firm increases her service level with an increasing price. The reason is, a greater price may increase the marginal profit of the firm, to capture more consumers, the firm will increase her personalized service level. But the relationship between the expected demand/profit and the price are complicated and non-linear. Because consumers misrepresent depending on the personalized service level which will impact on the additional profit and the service cost. To provide reasonable and smooth analysis of this paper, we didn’t show the details.
Based on Proposition 2, we derive the following corollary.
Corollary 4. If consumers misrepresent,
(1) When the market is fully covered, (i) if , , otherwise, ;. (ii) if ,, otherwise, ; .
(2) When the market is partly covered, (i); , . (ii); , .
Corollary 4 shows how the unit value of consumer’s privacy information and unit cost of personalized service impacts on the monopolistic firm’s optimal decisions when consumers misrepresent.
When the market is fully covered, meanwhile the unit cost of personalized service is low, a greater unit value of consumer’s privacy information leads to a higher personalized service level, because the marginal profit increases. Similarly, a greater unit cost of personalized service leads to a lower personalized service level, because the marginal profit decreases. But when the unit cost of personalized service is medium, the monopolistic firm doesn’t change her personalized service level when the unit value of consumer’s privacy information or the unit cost of personalized service increases, because in this case, the marginal profit is only relative with the price, and cost of personalized service equals to the additional profit. Then, Corollary 4(a) shows that a greater unit value of consumer’s privacy information leads to a higher expected profit, because the marginal profit increases, and a greater unit cost of personalized service leads to a lower expected profit, because the cost of personalized service increases and is greater than the additional profit.
Hence, when consumers misrepresent and the market is fully covered, the monopolistic firm should try to explore the value of consumer’s privacy information and reduce her unit cost of personalized service.
When the market is partly covered, a greater unit value of consumer’s privacy information leads to a higher personalized service level and captures more consumers, but get less profit. In this scenario, a greater unit value of consumer’s privacy information indicates a higher marginal profit, the firm increases her personalized service level to attract more consumers. But when the personalized service level increases, consumers will misrepresent more which may reduce the marginal profit, meanwhile, the cost of personalized service increases, hence, the expected profit decreases when the unit value of consumer’s privacy information increases. Then, a greater unit cost of personalized service leads to less personalized service level, less consumers but more profits. In this scenario, a greater unit cost of personalized service indicates that the firm costs more to provide a unit personalized service level. To maximize her profit, the monopolistic firm should decrease her personalized service level to reduce the personalized service cost, which results to a less consumer demand. But the marginal profit increases because the decrement of unit personalized service cost is greater than the decrement of the unit additional profit, hence, the monopolistic firm can get more profit with a higher unit cost of personalized service.
Hence, when consumers misrepresent and the market is partly covered, the monopolistic firm should be more cautious to explore the value of consumer’s privacy information and reduce her unit cost of personalized service.
4.3. Comparison Analysis
Consumers may misrepresent and impact on the monopolistic firm’s optimal strategies. In this section, we will compare the optimal strategies when consumers do not misrepresent with those when consumers misrepresent.
Based on Proposition 1 and Proposition 2, we firstly compare the optimal personalized service level, and analyze the effect of misrepresentation of firm’s personalized service level. We can get the following results:
Proposition 3. Based on the optimal personalized service levels in Proposition 1 and Proposition 2,
(1) if
i) When , ;
ii) When, ;
iii) When : a) If and , ; b) If or , .
iv) When ,.
(2) if
i) When , ;
ii) When , ;
iii) When , a) If or , ; b) If and , .
iv) When , a) if ,; b) if , ; where .
v) When ,;
vi) When , .
Based on the comparison results of and , we can have when the unit cost of personalized service is low, the monopolistic firm provides higher personalized service level if consumers mispresent. When the unit cost of personalized service is high, the monopolistic firm provides lower personalized service level if consumers misrepresent.
But when the unit cost of personalized service is medium, the comparison results vary with the unit value of consumer’s privacy information, the unit cost of personalized service and the product price. When the unit value of consumer’s privacy information is low, meanwhile the product price is high, the monopolistic firm provides higher personalized service level if consumers misrepresent. Otherwise, the monopolistic firm provides lower personalized service level if consumers misrepresent. When the unit value of consumer’s privacy information is high, meanwhile, the price is high, the monopolistic firm provides higher personalized service level if consumers misrepresent. But when the unit cost of personalized service is relatively high, the monopolistic firm also provides higher personalized service level if consumers misrepresent.
Hence, if consumers misrepresent, the monopolistic firm should be cautious to increases her personalized service level to attract more consumers. Only when the unit cost personalized service level is low, her optimal choice is increasing her personalized service level. But if the unit cost personalized service level is high, her optimal choice is decreasing her personalized service level.
Furthermore, based on Proposition 1 and Proposition 2, we compare the expected demand if the market is partly covered, and derive the following results.
Proposition 4. When the market is partly covered, if , ; otherwise, .
In Proposition 4, the market is partly covered, when the unit value of consumer’s privacy information is low, the monopolistic firm get less demand if consumers misrepresent. The reason is a low unit value of consumer’s privacy information means a low additional profit which may make the monopolistic firm reduce her personalized service level. Then a reducing personalized service level can’t attract more consumers which leads to a less consumer demand.
Proposition 4 indicates that consumer misrepresentation impacts on the demand of the monopolistic firm, and it varies with the unit value of consumer’s privacy information. When the unit value of consumer’s privacy information is low, consumer misrepresentation reduces the demand, otherwise, it enhances the demand.
Then, we compare the profit when consumers misrepresent and that when consumers don’t misrepresent. We have:
Proposition 5. (1) When the market is fully covered, if && , or && , ; otherwise, .
(2) When the market is partly covered, there exists a threshold , ; otherwise, .
Proposition 5 shows that even consumers misrepresent, the monopolistic firm still can be better off. Hence, in practice, the firm should not be severe about consumer misrepresentation.