Abstract
In light of recent policy discussions aimed at reforming Medicaid, it is important to understand how the elderly respond to changes in the incentives of Medicaid. This article estimates the effect of a decrease in the implicit tax of holding assets brought about by the Medicare Catastrophic Coverage Act of 1988. Using the Health and Retirement Study (HRS), I find that a $1 increase in state asset protections increased median total wealth holdings by $0.20, financial wealth by $0.04, and home equity by $0.27. As expected, larger responses are found for residents of states with income limits in place prior to the law change and for states that chose the highest level of protected resource amounts.
Medicaid is by far the most important provider of long-term care in the United States. The recent Great Recession both increased demand by an aging population for long-term care services and put pressure on state budgets leading to potential cuts in Medicaid services. As the solvency of the Medicaid program is discussed with an eye on future potential cutbacks and reforms, it is important to form an understanding of how the elderly respond to changes in Medicaid and more specifically its means tested nature.
The Medicare Catastrophic Coverage Act of 1988 (MCCA88) decreased the implicit tax of holding assets under Medicaid spend down. 1 Prior to MCCA88, spouses of institutionalized elderly were subject to high rates of “spousal impoverishment” because of strict income and asset spend-down requirements. 2 All assets owned jointly or solely by the institutionalized spouse and his income were eligible for asset spend-down. For this generation, the majority of income was earned by the husband who was more likely to get sick first. As a result, the community spouse, typically a female, had to subsist on a small social security (SS) income in her own name along with on average $2,500 in assets. These limited resources had to cover all of her expenses including home maintenance and repairs. Spousal impoverishment led to reports of a high occurrence of divorce, meant to protect assets for the community spouse, and a fear that those who did not divorce would need to apply for public assistance programs in order to survive. The federal government responded with MCCA88, which saw Congress increase both the asset and the income protections, ensuring that the community spouse had access to income above the federal poverty line and increased assets by decreasing the implicit tax of holding assets. The federal government set the minimum, $13,296, and the maximum of $66,480 amount of protected assets, with states choosing their actual limit in this range.
Federal passage of MCCA88 should have increased total wealth holdings of the community spouse for at least three reasons. First, MCCA88 decreased the implicit tax of holding assets by increasing the asset threshold beyond $2,500. One can consider this the accounting effect, meaning that for a given level of joint financial resources, a widow will emerge from a husbands’ death with more assets under the MCCA88 rules. Second, MCCA88 increased the income eligibility threshold beyond the Supplemental Security Income (SSI) limit and guaranteed spouses an income above the federal poverty level, allowing her to use income rather than assets to cover monthly bills, living expenses, and any unexpected costs. The increase in both thresholds should allow a spouse to increase asset holdings and maintain them, which should result in higher total wealth. Third, in addition, MCCA88 created an incentive effect, lowering the implicit tax imposed by Medicaid means testing, and should therefore have encouraged couples to accumulate more assets over their lifetime.
Unfortunately, relatively little empirical evidence exists concerning the effect of spousal impoverishment law changes on wealth holdings of the community spouse; see Gruber (2003) for a complete overview. While the estimates from the past literature have found little to no evidence of changes in wealth and savings as a result of the law’s adoption, these studies were plagued by inadequate data recorded on the elderly prior to the 1990s. In this article, I attempt to circumvent some of the difficulties that have inundated previous studies by using detailed data from the Health and Retirement Study (HRS) and using variation in the state-protected resource amounts (PRAs).
I investigate the largest group of elderly, widows, to measure their response to changes in the implicit tax of holding assets. I find the elderly are responsive, and more specifically, a $1 increase in the asset exemption for a state leads to a $0.20 increase in total wealth, $0.04 increase in financial wealth and actually increased home equity holdings among the elderly. This suggests that widows prior to 1988 did not have enough resources to perform maintenance on their homes and cover day-to-day living expenses, which indicates MCCA88 did help to alleviate the problem of community spouses’ impoverishment. As expected, I find larger behavioral responses for residents of the highest PRA states and residents of states with income limits in place prior to the law change.
The rest of the article is organized as follows: the second section includes the institutional detail of the law change and a description of the past literature. The third section explains the method and data used, while the fourth section gives the results. The fifth section discusses a series of robustness checks, and the final section provides the conclusions.
Background
Nursing home costs are typically large and unexpected with annual costs exceeding $70,000. Additionally, Dick, Garber, and MaCurdy (1994) reported that 12 percent of those needing a nursing home will need them for five or more years. Simple present value calculations of these expenses show that most asset portfolios are not sufficient to handle such expenses. Simultaneously, Brown and Finkelstein (2007) report demand-side and supply-side failures in the private long-term care insurance market and Medicaid crowd out demand for private long-term care insurance (see Brown and Finkelstein 2008). As a result, the private market has remained small which is exemplified by the following statistic: in 2000, $71 billion was paid out in the United States for long-term care services, 44 percent ($31 billion) consisted of Medicaid long-term care costs, while private long-term care insurance plans only paid for $300 million (0.04 percent). 3
However, in order to qualify for Medicaid, individuals must pay for nursing home care costs out of pocket until they meet their states’ income and asset eligibility levels. In addition, there is a thirty-month look-back period. 4 For the working-age population generally only the poor are able to qualify for means-tested social insurance programs; however, elderly with high income and assets can actually qualify for Medicaid because most states expand their Medicaid-eligible elderly population to include those whose current income is inadequate to pay for health care costs. These elderly are deemed “Medically Needy” and are allowed to spend down their income and wealth on health related expenses in order to satisfy their states’ income and asset eligibility restrictions. As of September 1987, thirty-one states had no fixed upper limit with regard to the total amount of income an institutionalized elderly Medicaid recipient could have (Carpenter 1988).
Spousal Impoverishment
Prior to MCCA88, the community spouse faced a high probability of being impoverished or forced to live with an income below the federal poverty line when their institutionalized spouse entered a nursing home, because all income and assets owned either jointly or solely by the institutionalized spouse were eligible for spend down. For this cohort, the institutionalized spouse was typically the sole earner, which left the community spouse, typically a female, with income around the SSI level ($340 per month in 1993) and about $2,500 in resources that were most likely insufficient to cover and maintain her costs of living and the upkeep of her home. 5
This led to the impoverishment of many community spouses and, in some cases, divorce in order to protect assets for the community spouse. Congress responded by enacting the Medicare Catastrophic Coverage Act of 1988. 6 The law set up protective measures to set aside enough income and resources to allow the community spouse to live in a manner that did not result in her impoverishment (Congressional Research Service 1993). The law affected the look-back period (increased from twenty-four months to thirty months) and the spousal share for both income and assets (PRA), in order to protect elderly women by making sure they could cover daily living expenses, and to prevent her from needing to go on other public assistance to sustain herself.
After federal adoption of MCCA88, the community spouse was entitled to a protected amount of the couple’s combined resources to use for living and maintenance. 7 The law decreased the implicit tax of holding wealth that the elderly faced from means testing for Medicaid eligibility. Prior to 1988, assets owned either jointly or by the institutionalized spouse were eligible for spend-down, but after MCCA88 all assets owned by both spouses or jointly owned assets were compiled together and divided in half, making up each spouse’s share. In 1991, the state maximum for the spousal share of protected resources could not exceed $66,480 and the state minimum set up by federal law was $13,296. These ceilings and floors are adjusted by the consumer price index (CPI) each year to ensure the community spouse is still receiving the same amount of protection in real terms. 8 Table 1 shows the state limits for community protected assets valid as of January 1, 1991, as reported in table III-14 of the Congressional Research Service (1993). Thirty states chose to be at the federal minimum, sixteen at the federal maximum, and five chose an asset limit in between. 9
1991 State-Protected Resource Amounts (PRAs).
Source: Table III-14 of Congressional Research Service (1993).
If the community spouse’s half of the resources are insufficient to meet the state limit, then the institutionalized spouse contributes a share of his resources until the threshold is achieved. For example, consider a couple with $25,000 in assets and a state with the federal minimum standard of $13,296. The community spouse’s half of the assets would come to only $12,500, which is less than the state minimum. As a result, the institutionalized spouse would contribute $796 to the community spouse. In order to qualify for Medicaid, the institutionalized spouse would then have to spend-down the remaining $11,704 of his resources until he hit the $2,500 asset limit.
Now consider a couple that lives in a state with the maximum protection level of $66,480 and the couple has $200,000 in resources. The community spouse’s share of the resources comes to $100,000, which is above the maximum protection level of assets. She would have to contribute $33,520 in assets toward the nursing home care of her institutionalized spouse. Once this transfer of assets from the community spouse toward the nursing home costs of the institutionalized spouse had been made, then the institutionalized spouse would be considered eligible for Medicaid financed nursing home services.
Because the motivation for this law was to prevent spousal impoverishment, MCCA88 also set up income standards to ensure the community spouse had enough income to pay her bills and meet her basic needs. As reported by the Congressional Research Service (1993), as of January 1, 1991, the community spouse had to receive an income greater than 122 percent of the federal poverty line, represented by $856 per month. This was increased on July 1, 1992, to 150 percent. If the community spouse earned a small income, as was typical for females, the institutionalized spouse could transfer part of his income to the community spouse in order to augment her income up to the state standard and above the federal poverty line. The exact determination of the income she was entitled to was dependent on a number of factors, including her actual housing costs and the presence of any minor or disabled children in the household.
Past Literature
There exist a number of studies on the impact of means testing on asset behavior, with the exception of DeNardi, French, and Jones (2006) and Neumark and Powers (1998) most do not focus on the elderly. 10 Three strands of literature have particular relevance to studying the effect of MCCA88 on widow portfolio decisions. The first and most relevant strand investigates the adoption of MCCA88 and asset levels. Norton and Kumar (2000) compared the assets of a community spouse and single person after the passage of MCCA88. With use of the National Long Term Care Survey, which consists of a sample of elderly with chronic functional disabilities, they do not find any difference in the savings behavior in their sample or that MCCA88 achieved any of its goals. However, the selected sample of elderly with functional disabilities may have biased the results.
The second strand focuses on Medicaid, spousal impoverishment, and nursing home use. Because Medicaid has a spend-down component for eligibility, economists would predict a large spend-down once a person entered a nursing home. Individuals would pay for care out of pocket until their assets and income met their states’ eligibility thresholds. However, the literature has not found that to be the case; see Rice (1989) and Norton (1995). Norton and Kumar (2000) found that MCCA88 changes had no effect on the probability of being on Medicaid and the probability of being in a nursing home.
The third strand examines the impoverishment of widows, an understudied group. Hurd and Wise (1989) confirm that widows make up the majority of the elderly and are also more likely to be impoverished, even when they were not impoverished as part of a married couple. In support of this fact, Sevak, Weir, and Willis (2003) report that in the 1970s conditional on being a new widow, 73 percent became poor, but this decreased to between 12 percent and 15 percent in the 1990s. The time frame suggests that the 1988 spousal impoverishment protections could have contributed to this decline in new widow impoverishment due to the lower implicit tax on holding wealth after the MCCA88 law adoption.
Data and Econometric Specification
The ideal study to measure the effect of MCCA88 changes on elderly wealth portfolios would compare two couples, one just before 1988 and one just after 1988, in which a major health shock required nursing home care. Ideally, both would have modest wealth prior to the health shock, enabling the researcher to estimate the true impact of the law change on elderly wealth holdings. However, performing this ideal study is not possible because of the insufficient data kept on the elderly prior to 1993. I augment the literature by using the HRS and examining specific state PRA limits.
The HRS is a biennial data set that began in 1992 for younger cohorts and in 1993 for the Assets and Health Dynamics of the Elderly (AHEAD) cohort of elderly seventy and older. The data follow the same sample every two years and add in younger and new respondents in later years. It includes detailed information on financial, health, family dynamics, and demographic variables on both noninstitutionalized and institutionalized elderly. The restricted access geocoded HRS data also allow me to include specific state asset limits in the analysis because it contains locational information for each respondent, including their state of residence.
Unfortunately, the detailed information on the AHEAD cohort of the HRS elderly data was not collected until 1993, and as a result, information does not exist on nursing home use or Activities of Daily Living (ADLs) in 1988 that could be used to measure the use of a nursing home or potential need for one. The 1993 wave of the HRS does, however, have the ability to identify those that lived through the death of a spouse, before and after the law change. I restrict my sample to widows, which make up the largest segment of elderly and to date have been vastly understudied in the literature. In addition, Venti and Wise (2004) find the elderly do not make housing portfolio changes unless facing a health shock or widowhood. I then separate widows into two groups, those widowed before 1988 and those widowed after 1988, for my analysis. Table 2 presents demographic characteristics for all widows (column 1), widows prior to 1988 (column 2), and those widowed after 1988 (column 3).
Sample Size, Properties, and Statistics.
One problem with this estimation technique is that any household in which one spouse is in a nursing home in 1988 but does not die until 1989 will be counted in the post-1988 widow sample even though they spent down their assets to qualify for Medicaid before the law change, which results in a downward bias of the coefficients estimated. The incentive effect is also biased toward zero because the most important household wealth decisions tend to be made while the husband is still alive. Another worry is that those who have been widowed longer have less wealth because they have had a longer period of time they needed to live on those assets. I attempt to circumvent this as explained in the subsection Widows 1983–1993.
I examine the following three main outcomes: total wealth, financial wealth, and home equity. This is important because of Medicaid’s differential treatment of owner-occupied housing assets. Owner-occupied housing assets are exempt from the Medicaid eligibility decision and therefore from spend-down requirements. Policy makers and economists have long worried about the distortion created by Medicaid’s incentive to overinvest in housing assets due to the protected status of owner-occupied housing. However, it is possible that prior to 1988, even though the house was a protected asset, the community spouse was destitute to such an extent that she was forced to either sell her home, due to her inability to pay for upkeep and day-to-day expenses, or to spend down her home equity implicitly by not keeping up-to-date on maintenance for the house, which is consistent with Davidoff (2006). If this was in fact the case, after 1988 she no longer needed to defer maintenance because she was guaranteed to remain above the poverty line by MCCA88 and had greater assets and income at her disposal to pay for daily living and costs associated with maintaining and caring for a home.
If the elderly are responsive, then the state specific amount should impact asset holdings. More formally, let i index person and s index state. Then the econometric specification is
where D After1988 is a dummy variable that takes on a value of one if the respondent was widowed after 1988 and a value of zero otherwise. SS income minority status, number of kids, education, self-reported health, age, age when widowed, smoking status, SSI status, and basic demographic variables are included in the vector X. Because there is not state-by-time variation in the state PRAs, state fixed effects cannot be used. 11 Instead, I include a number of other state characteristics to account for differences in state economic environments, such as the unemployment rate, per capita income, housing price index, and average cost of a nursing home day in each state. 12 These are shown in the vector of state variables, γ. The key variable of interest is the interaction between a dummy variable signaling being widowed after 1988 and the state chosen PRA limit. The coefficient of interest, α, represents the effect of $1 increase in the state PRA on total wealth holdings.
The individual demographic variables are included to help control for potential sample selection concerns. I include SS income because it is not endogenous, as it is determined by decades of work experience and therefore cannot be altered at the time of survey. Smoking, SSI, and self-reported health are likely factors in determining Medicaid need, especially considering that in most states SSI recipients are automatically eligible for Medicaid. I control for age and age widowed because it is likely that those that are older have fewer assets to live off of and those that have been widowed for longer periods likely have assets remaining.
Results
Total Wealth
Table 3 shows estimates of equation (1) using the HRS and augments the literature by examining the effect of a $1 increase in the PRA. Because of the rightward skewed nature of the outcomes of interest, I perform a median regression analysis. Column 1 examines the specific state spousal limit and finds a $1 increase in the state PRA will increase total wealth holdings after the law change by $0.20, not statistically significant. 13 However, the majority of states chose either the minimum (thirty states) or maximum (sixteen states), with only five states choosing an amount in between. As a result, making the spousal limit a continuous variable may not be the best estimation strategy. Instead, column 2 includes indicator variables for whether the state was at the maximum PRA or in the middle group, with residents of states choosing the minimum being the excluded group. I find that a state moving from the minimum to the maximum PRA increases total wealth holdings by $10,655, statistically significant at the 10 percent level and moving from the minimum to the middle range results in a decrease of $4,550, though it is not precisely measured and mean estimates (not shown) reflect a positive insignificant response. Part of this likely reflects the fact that there are small differences between the minimum limit ($13,296) and the middle PRA states (range of $20,000–$31,290), while there is more than a $50,000 difference between the minimum and maximum states. Column 2 suggests that moving to the maximum level draws the largest behavioral response.
Median Effects of MCCA88 on Wealth Decisions.
Note: TW = total wealth; FW = financial wealth; HE = home equity; PRA = protected resource amount. This table investigates the effect of MCCA88 on wealth portfolio behavior. All columns also include a categorical variable for self-reported health. Columns 2, 5, and 8 also include variables indicating if it is a high or middle PRA state. Columns 3, 6, and 9 also include variables for limit, interaction between PRA and limit, and interaction between after1988 and limit. Standard errors are presented in brackets.
However, the law change should have differentially affected states that chose the same PRA because some of those states had income limits for Medicaid recipients in place prior to the law change and other states did not (see Carpenter 1988). A priori, we would expect states with limits in place prior to MCCA88 to have the biggest behavioral response as they saw the biggest decrease in the implicit tax of holding wealth. I find that looking at the interaction between the spousal limit, being widowed after 1988 and having an income limit prior to 1987, a $1 increase in the PRA increases wealth holdings among the elderly by $1.21, statistically significant at the 1 percent level. Columns 2 and 3 suggest that even only looking at the state specific amount is missing the marginal responses by those we would expect to be most affected, high limit states and residents of states with income limits in place prior to the law change.
One potential worry is reverse causality, meaning that the highest-asset states are those that chose the maximum level asset protection and the low-asset states, conversely, chose the minimum level asset protection. The wealth distributions of my HRS sample for the three outcomes of interest are important in determining how great a factor this proves in the analysis. States with the maximum PRA have a median total wealth of $52,000, median financial wealth of $2,300, and median home equity of $27,000. The minimum PRA states have a median total wealth of $45,200, median financial wealth of $2,500, and median home equity of $30,000. The differences in the median values are small, suggesting that any reverse causality is weak.
Financial Wealth
To augment the case on wealth holdings among widows, equation (1) is estimated using financial wealth as the dependent variable. Owner-occupied housing is differentially treated by Medicaid because it is an exempt asset from spend down and determining eligibility. The incentives from the means tested program imply that a priori we expect the change in asset behavior should be fully encompassed into financial wealth changes due to Medicaid’s special treatment of owner-occupied housing assets. Table 3 also presents the results when estimating equation (1) with financial wealth as the dependent variable and using median regression techniques. These estimates are also biased downward to zero, and therefore finding any effect would have importance. Column 4 of table 3 presents the results for median estimation with only considering the state specific PRA. A $1 increase in the spousal impoverishment limit results in widows after 1988 having $0.04 more in financial assets, statistically significant at the 5 percent level. Column 5 incorporates low, middle, and high PRAs and finds moving from the lowest to the highest PRA increases financial wealth by $1,870, statistically significant at the 5 percent level. Moving from low to middle (only five states) is insignificant and negative; however, the mean is positive, showing that clearly different parts of the distribution are behaving differently. Column 6 shows residents of states with limits prior to the law change have a response not statistically different than zero.
Home Equity
While the total wealth and financial wealth estimates suggest that the elderly are responsive to changes in the incentives from means-tested programs, it is clear that not all of the total wealth changes were encompassed in the financial wealth coefficients as a priori was expected. Even though owner-occupied housing assets have a protected status for Medicaid eligibility both before and after MCCA88, it remains possible that some of these widows prior to 1988 were destitute to such an extent that they were forced to sell the house or spend down home equity through lack of maintenance because of inability to pay for its associated expenses and day-to-day upkeep. This has not been considered by the previous literature on MCCA88, but is consistent with Davidoff’s (2006) suggestion that the elderly do spend down their home equity through lack of maintenance as a way to spend down their housing assets without selling the house and stay more consistent with the life-cycle model. The personal finance industry estimates that maintenance can be anywhere from 1.4 to 4 percent of the house’s value per year. Based on the sample mean of home equity for those widowed prior to 1988, this is about $600 to $1,700. Prior to 1988 a community spouse would have access to $2,500 in assets and $340 per month in income, which would not be sufficient to cover these home maintenance expenses. These are lower bound estimates for maintenance, as they are based on mean home equity rather than the “market value” of the home. As a result, these severe circumstances of poverty could occur instead with widows prior to 1988 having less home equity relative to those widowed after 1988.
Table 3 also includes the results when home equity is the dependent variable in columns 7 through 9. The state-specific protected asset amount shows that a $1 increase in the protected asset limit results in $0.27 more being held in home equity by the elderly widowed after 1988, statistically significant at the 1 percent level. Column 8 shows moving from low PRA to high PRA increases home equity by $15,368, statistically significant at the 1 percent level. Moving from low to the middle is not statistically significant. In column 9, I find residents of income limit states increased home equity by $0.65 statistically significant at the 1 percent level. 14
Robustness Checks
Placebo Tests
One potential worry about these results is that trends exist in portfolio wealth changes prior to the law adoption or that the law changes produced anticipatory effects. In order to examine this, I use a placebo test that essentially pretends that the law was adopted in 1985 instead of 1988. I limit the sample to include only those widowed prior to 1988, because those widowed after 1988 would be reacting to the actual law change, which would confound my estimates related to the placebo law change. These results are presented in table 4 with median regressions for all three outcomes of interest. The table columns are set up in the same format as table 3.
Placebo 1985 Law on Median Wealth Decisions,
Note: TW = total wealth; FW = financial wealth; HE = home equity; PRA = protected resource amount. This table investigates the effect of placebo 1985 law change on wealth portfolio behavior. The sample is limited to only those widowed prior to 1988 to not confound the placebo test. All columns also include a categorical variable for self-reported health. Columns 2, 5, and 8 also include variables indicating if it is a high or middle PRA state. Columns 3, 6, and 9 also include variables for limit, interaction between PRA and limit, and interaction between after1988 and limit. Standard errors are presented in brackets.
Column 1 shows a $1 increase in the PRA actually decreased total wealth by $0.05. Next, there is a decrease in total wealth when moving from a low PRA state to a high PRA state (column 2) and also in states with income limits in place prior to the law change (column 3). All three of these results show that there do not appear to be anticipatory effects of the law change for total wealth. For financial wealth, column 4 (state amount) shows a small negative response, moving from high to low increases financial wealth by $686, which is statistically insignificant and smaller than the measured response of $1,870 found in table 3. Finally, for the income limit states prior to the law change, there is a $0.08 change statistically significant at the 5 percent level, which is similar to the result found in table 3. Columns 7, 8, and 9 consider home equity and show that there is a negative and statistically insignificant response for the state PRA, moving from low to high PRA states, and for states with income limits in place prior to the law change. Table 4 provides evidence that anticipatory effects do not appear to be a problem.
Widows 1983–1993
There is still a potential concern that those who have been widowed for longer periods of time have less assets than those widowed more recently. To test for this, I limit the sample to those widowed within five years of the law change (1983–1993) and then examine the effect of the 1988 law change. If my results in table 3 are to be believed, then I should still find that the 1988 law change resulted in asset changes among the elderly. Table 5 displays these results and finds similar results to those displayed in table 3, except that the estimates are less precise and somewhat smaller in magnitude, with the exception of columns 5 and 6, which become statistically insignificant and negative. 15 However, I still find that there is a behavioral response, suggesting that table 3 is displaying a behavioral response to the law change and not just measuring that elderly who have been widowed for longer periods of time have less assets.
Median Wealth Decisions for widows 1983–1993.
Note: TW = total wealth; FW = financial wealth; HE = home equity; PRA = protected resource amount. This table investigates the effect of MCCA88 on wealth portfolio behavior for those widowed from 1983 to 1993. All columns also include a categorical variable for self-reported health. Columns 2, 5, and 8 also include variables indicating if it is a high or middle PRA state. Columns 3, 6, and 9 also include variables for limit, interaction between PRA and limit, and interaction between after1988 and limit. Standard errors are presented in brackets.
Conclusion
This article provides insight into how the elderly respond to the incentives from a means tested program by using the decrease in the implicit tax of holding assets brought about by MCCA88, which the government adopted in order to prevent future and continued occurrences of spousal impoverishment. The law increased the protected spousal share for both income and assets. Comparing those widowed prior to and after 1988 shows that widows have more total wealth, financial wealth, and home equity after the law change. I find evidence that a state’s PRA impacts wealth holdings of the elderly, with the majority of the behavioral change happening for residents of high PRA states and those with income limits in place prior to the law change. This finding also may provide important guidance for future policy decisions, because clearly widows, the largest segment of the elderly and the one most likely to be impoverished, are responsive to law changes.
Footnotes
Acknowledgment
The author would like to thank Gary Engelhardt for helpful comments.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.