On adaptation, life-extension possibilities and the demand for health
是由Smoking, health, risk, and perception一文所提"Our framework is inspired by Gjerde et al. (2001), which presents a formal model of health adaptation based on Grossman (1972a).
心得要點
1."適應過程是被用來形容，人有能力應付或適應惡性變化的健康"，也可以解釋成健康適應能力。
2.格羅斯曼模式中適應是一個重要的概念，其對健康的投資行為將受適應的影響，即某行為適應良好，即有好的健康效果，即表示這行為是有良好的健康適應。
3.主要的論點為適應與健康的相關因素：1.與意外2.與疾病及慢性並有關，但隨著年齡的增加而健康的變化也是重要的
4.故適應是一個以健康為目標的過程，這個過程是有認知的、情感的，是改造的活動、對此活動的價值感受，而方法上有技能的增加、活動的調整、目標的調整、降低期望、提高淡泊和改變觀念等
5.提出健康會因年齡愈高健康愈壞的證據，但研究發現愈老的人雖然健康情形不如年輕人，但確自認為自己是健康的，也就是在自我健康認知上與實際會有落差，這表示老的人是注重健康心態，作者推論是老的人更習慣及更多時間來適應其身體上不健康的情形。
6.作者提出以上適應與老化關係的文獻，來支持要發展一個健康適應的測量來建立理論與量化分析以解釋個人的行為。
7.論文結論：適應對健康的兩個需求
1.適應會隨時間減少對健康投資的意願，也就是說愈適應，就不會去對健康進行投資。
2.同樣的適應覺知，引起對健康計畫的投入
但是適應並不是延長壽命而引起健康投資的主要因素，即其效果不高，它是與健康投資、消費的路徑相同，即對高價醫藥照顧、以較多時間觀注健康有較高的效果。
就此篇的想法是其運用複雜的模式來描述適應與健康及年齡的關係，此模式帶給我目前論文的啟發
文章重點
Yet another type of internal reference points is adaptation theory.
The concept of adaptation originates from biology where it is used to describe adjustments to the conditions under which species must live in order to survive.
Adaptation processes are also discussed in economic literature on preference formation (see Ng and Wang 1993; Rabin, 1998; Frank, 1989) as well as in studies on health status evaluation where they are used to describe the ability individuals have to cope or adapt to malign changes in health.
The theory postulates that humans are sensitive to context, frame, or the current situation rather than absolute characteristics, only.
In this perspective, adaptation suggests mechanisms different from those applied in traditional approaches on health demand such as the pioneering works of Grossman (1972a,b) and subsequent extensions (see, e.g., Muurinen, 1982; Wagstaff, 1986; Ehrlich and Chuma, 1990; Ried, 1998; Eisenring, 1999; Jacobson, 2000).
Consequently, it would be of interest to investigate whether adaptation processes have implications for the results arrived in Grossman types of models, especially since some of their implications are contradicted by available evidence.
然而，另一種類型的內部參考點是適應理論。這個概念源自生物學適應它被用來描述調整的條件下，物種必須住在為了生存。
適應過程還討論了在經濟文獻上的偏好形成（見吳和王1993年，拉賓，1998年弗蘭克，1989年）以及在健康狀況評價的研究，他們被用來形容人有能力應付或適應惡性變化的健康。
該理論認為，人類是敏感的背景，框架，或者當前的形勢，而不是絕對的特點，只。
從這個角度來看，不同的適應機制，從這些建議適用於傳統的方法對健康的需求，如開拓工程格羅斯曼（1972a，b）和隨後的擴展（例如，見 Muurinen，1982;瓦格斯塔夫，1986;埃利希和楚瑪，1990年;里德，1998年; Eisenring，1999;雅各布森，2000）。
因此，這將是利益，以調查是否適應過程所產生的影響的結果抵達格羅斯曼類型的模型，特別是因為他們的一些
含義是相矛盾的證據。
因此可了解
1."適應過程是被用來形容，人有能力應付或適應惡性變化的健康"，也可以解釋成健康適應能力。
2.Grossman (1972a,b)是有名健康適應模式提出者
Grossman, M. (1972a): On the Concept of Health Capital and the Demand for Health,
Journal of Political Economy, 80: 223-255.
Grossman, M. (1972b): The Demand for Health: A theoretical and empirical
investigation, National Bureau of Economic Research, Occasional Paper 119,
Columbia University Press, New York.
對Grossman模式的說明與其原模式建構的原因
In the Grossman model, health is considered a capital stock that increases due to investment (buying health services, medical goods, or spending time on healthy activities), and decreases in response to an advancing age.
According to this model, there are three reasons why individuals demand health.
First, health is a consumption commodity in the way that it directly enters the individual utility function.
Good health implies higher utility than bad health for a given consumption level.
The second reason to demand health is based on health as an investment commodity.
Health determines the total amount of time available for market and non-market activities, e.g., bad health gives more sick days than good health.
Available time increases in health, which again represents a monetary value.
This may be thought of as a return to investment in health.
The third reason follows from health determining the length of life.
A good health condition may give a longer lifetime.
Of the three reasons to demand health, adaptation will be important only for health as consumption good, i.e., how much the utility will be affected from changes in the objective health state.
在格羅斯曼的模式，被認為是健康資本存量的增加，因為投資（購買醫療服務，醫療用品，或花費時間對健康的活動），並減少響應一個年齡的老化。
根據這個模型，有三個原因，個人需求的健康。
首先，健康是消費商品的方式，直接進入個人的效用函數。
良好的健康意味著更高的效用比一個給定的不良健康消費水平。
第二個理由是基於需求的健康保健作為投資商品。
健康決定了總金額的時間可用於市場和非市場活動，如不良的健康提供了更多的病假比身體健康。
可用時間增加在健康，這又是一個貨幣價值。
這可能被認為是回歸到投資的健康。
第三個原因如下決定長度從健康的生活。
良好的健康狀況可能會更長的壽命。
在這三個方面的原因，要求健康，適應將是重要的消費只為健康良好，即有多大的效用將受到影響，從變化的客觀健康狀況。
格羅斯曼模式中適應是一個重要的概念，其對健康的投資行為將受適應的影響，即某行為有好的健康效果，即表示這行為是有良好的健康適應。
We do not know any other studies that formalise adaptation processes.
In this paper, therefore, an effort is made to integrate adaptation to ageing in a formal model framework.
This means that instead of studying rapid changes in health due sickness or accidents, we concentrate on the natural decline in health, as one grows older, i.e., how we adapt to becoming old.
In order to keep the analysis tractable we restrict ourselves to the pure consumption model of Grossman (1972a,b).
The model is extended in yet another direction, by leaving the common assumption of a fixed lifetime or an endogenous lifetime being determined by the stock of health capital reaching a minimum level (see, e.g., Wolfe, 1985, Ehrlich and Chuma, 1990, Ried, 1998, Eisenring, 1999 and Jacobson, 2000).
Rather we prefer to introduce uncertainty into the model by modelling a probability of life-termination decreasing in the stock of health capital (i.e., the random date of death is conditioned upon objective health status).
This allows us to split the demand for health in two parts, as a consumption commodity and as a mean to extend life.
Only the first part is affected by adaptation.
我們不知道任何其他的研究，正式適應過程。
在本文中，因此，努力向整合是適應老齡化的一個正式的模型框架。
這意味著，而不是學習的快速變化，因疾病或意外事故的健康，我們專注於自然下降，健康為一體的長大，也就是說，我們如何適應成為歷史。
為了保持我們的分析聽話限制自己的純消費型的格羅斯曼（1972a，b）項。
該模型是在另一個方向擴展，留的共同假設一個固定的壽命或內源性的壽命是由股票的健康資本達到最低水平（見，例如，沃爾夫，1985年，艾氏和楚瑪，1990年，里德1998年，Eisenring，1999年和Jacobson，2000）。
相反，我們寧願不確定性引入到模型建模概率生命的終止減少在股市的健康資本（即隨機死亡日期的條件是客觀的健康狀況）。
這使我們分裂的需求健康兩部分，作為消費商品，並作為平均延長壽命。
只有第一部分是受適應。
文獻探討
In the literature, adaptation processes are mainly discussed
i) in the context of abrupt and unexpected changes in health conditions and
ii) for individuals with handicaps and chronic illnesses.
However, adaptation may also be relevant in the context of a
gradually declining health due to an advancing age.
The fact that health deteriorates with age is common knowledge and most likely people realise that their future evaluations of health will be conditioned on age itself.
In this perspective it seems adequate to integrate adaptation in a health planning perspective.
在文獻中，主要討論適應過程
i）在背景下突然和意外的變化，健康狀況和
ii）為個人與殘疾和慢性疾病。
然而，適應可能也有關係的背景下一個
健康逐漸下降，由於一個前進的時代。
事實上，隨著年齡的健康惡化是常識和最可能的人認識到他們今後評估的健康會受到自身條件的年齡。
在健康計畫的觀點來看，人是缺乏整體合性的適應。
主要的論點為市適應與健康的相關因素：1.與意外2.與疾病及慢性並有關，但隨著年齡的增加而健康的變化也是重要的
According to Heyink (1993, p. 1332), adaptation may be defined as “an intrapsychic process in which past, present, and future situations are circumstances given such cognitive and emotional meaning that an acceptable level of well-being is achieved”.
Mentzel et al., (1999) perceive adaptation as the alteration of activities, desires, goals, and values in response to changes in health states and suggest six different factors all considered to be potential elements of adaptation.
These are; skill enhancement, activity adjustment, substantive goal adjustment, lowered expectations, heightened stoicism and altered conception of health.
The same study distinguishes adaptation processes both from initial shocks related to health state changes and the increased knowledge that arises from experiencing adverse health conditions.
據 Heyink（1993年版，第1332），適應可以被定義為“內心的過程，過去，現在和未來的情況是這樣的情況下給予的認知和情感的意思是可以接受的水平的福祉，是實現”。
Mentzel等人（1999）認為適應與改造的活動，願望，目標和價值觀為響應健康狀態的變化，並提出六種不同的因素都被認為是潛在要素適應。
這些，提高技能，活動的調整，實質性的目標調整，降低期望值，提高淡泊和改變觀念的健康。
同樣的研究區別適應過程都從最初的衝擊與健康狀態的變化和增加的知識，來自經歷的不良健康狀況。
故適應是一個以健康為目標的過程，這個過程是有認知的、情感的，是改造的活動、對此活動的價值感受，而方法上有技能的增加、活動的調整、目標的調整、降低期望、提高淡泊和改變觀念等
There is some empirical evidence supporting adaptation processes when health deteriorates naturally over time.
In health surveys for Norway conducted by Statistics Norway, see SSB (1999), elderly people in general consider their health as good, even if many of them reported serious or less serious illnesses or worries.
For people above age 80, 20 per cent reported bad health.
This is a bit surprising as 27 per cent of the respondents above age 80 reported that they had an illness that strongly affected their everyday life.
SSB suggests that the reason may be that health expectations are reduced when one live as long as 80 years or more.
Cassilleth et al., (1984) found, in a study examining 758 patients, that older people seem to develop more effective skills with which to manage stressful life events.
”There may be a biological, evolutionary advantage for older patients, enabling them to adapt to illnesses that are epidemiologically associated with advancing years” (p. 509).
Van Maanen (1988) reports studies among self-defined healthy American born elderly and ill-healthy British born older persons.
The results indicate that many dimensions other than the absence of disease and illnesses determine the perception of health.
The older the person, the more emphasis was placed on health as a state of mind, even in situations of a gradually falling body.
Groot (2000) found elderly people to report better health than younger people.
One reason may be that elderly people may be more adaptive
than younger people: “Older people may have become more accustomed and have had more time to adapt to their health impairments” (p. 413).
有一些經驗證據支持適應過程時健康惡化，自然隨著時間的推移。
在挪威進行的健康調查由挪威統計局，看到國家統計局（1999），老年人普遍認為自己的健康良好，即使其中許多報導嚴重或不太嚴重的疾病或憂慮。
對於 80歲以上的人，20％報告不良健康。
這有點令人驚訝的27％以上的受訪者報告說，他們 80歲有一個疾病，嚴重影響他們的日常生活。
國家統計局認為，其原因可能是健康的期望是當一個人生活減少只要80年或更長時間。
Cassilleth等人（1984）發現，在一項研究中758例檢查，即老年人似乎更有效的技能開發可用於處理壓力的生活事件。
“有可能是生物進化優勢，為老年患者，使他們能夠適應疾病是
流行病學與推進年“（第509頁）。
凡Maanen（1988）的研究報告中自定義的健康美國出生的老人和病人健康的英國出生的老年人。
結果表明，許多方面比其他沒有疾病和病症確定感知的健康。
老一輩的人，更強調的是作為一種對健康的心態，即使在一個逐漸下降的情況下身體。格魯特（2000）發現老人的報告比年輕人更健康。
其中一個原因可能是老年人可能更適應
比年輕人：“老年人可能變得更習慣和有更多的時間來適應他們的健康障礙”（第413頁）。
提出適應會因年齡愈高健康愈壞的證據，但研究發現愈老的人雖然健康情形不如年輕人，但確自認為自己是健康的，也就是在自我健康認知上與實際會有落差，這表示老的人是注重健康心態，作者推論是老的人更習慣及更多時間來適應其身體上不健康的情形。
Findings from studies on adaptation have also triggered a debate on whom to ask about the utility of health states (patients, health personnel, or the general public) and whether patients, if asked, should report ex-ante or ex-post utilities.
E.g., Adang (1997) found that that people who have been through successful transplants assess their pre-transplant quality of life lower relative to assessments made before the transplants took place.
Also, Sackett and Torrance (1978) found that patients rated the value of an impaired state of health more highly than the general public, suggesting that people with deteriorating health adapt to their health condition over time.
從研究結果的適應也引發了一場辯論，誰詢問有關公用事業的健康狀態（患者，醫務人員，還是普通公眾），以及是否患者，若問，應報告事前或事後工具。
例如，阿當（1997年）發現，人們誰已通過評估其成功移植移植前的生活質量相對較低，以評估之前發生的移植。
此外，Sackett和托倫斯（1978）發現，患者的額定價值受損的健康狀況更加高度比一般市民，提示人們適應與健康惡化的健康狀況隨著時間的推移。
This evidence suggests that people may adapt to a lower health level over time.
One implication is that even if one believes that the adaptive behaviour should not be taken into account in health policies such as allocating scarce resources, adaptation may be important in explaining behaviour, such as the demand for medical care.
We, therefore, include an adaptive health measure in a theoretical and numerical analysis explaining individual behaviour.
這些證據表明，人們可能適應較低的健康水平隨著時間的推移。
一個含義是，即使有人認為，適應行為不應該考慮到衛生政策，如分配稀缺資源，適應可能是重要的解釋行為，如對醫療的需求。
因此，我們有一個自適應的衛生措施在理論和數值分析，解釋個人的行為。
作者提出以上適應與老化關係的文獻，來支持要發展一個健康適應的測量來建立理論與量化分析以解釋個人的行為。
3. THE MODEL
In this section we present a theoretical model, which is based on the pure consumption model of Grossman but modified in two respects.
First, adaptation processes are introduced, and second, we apply a probabilistic approach to life termination (uncertain lifetime).
3。的模型
在本節中我們提出了一個理論模型，它是基於純粹的消費模式的格羅斯曼但修改在兩個方面。
首先，適應過程介紹，第二，我們應用概率的方法來結束生命（不確定的壽命）。
.....
4. NUMERICAL RESULTS
There are several difficulties in characterising optimal paths and conducting comparative dynamics in a continuous time model with four stock variables (see also paragraph 4.3 below).
For this reason we apply a numerical version of the model to explore the impacts of adaptation on health stock and medical care.
The model specification and parameter values are given in Appendix 1.
Some important assumptions are, however;
(i) an additive utility function in consumption and health, and
(ii) a Weibull distribution to characterize the hazard rate function.
The calibration of the benchmark scenario with no adaptation (GMEN, Grossman Model ENdogenous hazard) was conducted in order to reach realistic age profiles for the health variables, consumption, as well as for the contingent probabilities for the
occurrence of death.
Health stock and consumption paths are calibrated to reach their
maximal values at young ages (30) and the mid-phase of life (50), respectively.
The first is an assumption, while the second is based on empirical evidence from the US and the UK (Attanasio and Banks, 1998), see also footnote.
To reach a realistic development in the contingent probabilities for the occurrence of death, we calibrated the model to reproduce a realistic expected length of life estimate for an individual
living in an industrialised country; see, e.g., SSB (2000).
4。數值結果
有幾個困難的最佳路徑和特徵進行比較動態的連續時間模型有四個股票變量（見上文第4.3段）。
為此，我們應用數字版的模型，探討了對健康影響的適應股票和醫療。
該模型的規範和參數值列於附錄 1。
一些重要的假設，然而;
（一）添加劑的效用函數消費和健康，
（二）Weibull分佈來刻畫風險率函數。
校準的基準情景，沒有適應（GMEN，格羅斯曼模型內源性危害）進行，以達到逼真的年齡分佈為變量的健康，消費，以及隊伍的概率為
發生死亡。
健康股市和消費路徑校準達到其
最大的價值在年輕的年齡（30歲）和中期階段的生活（50），分別。
首先是一個假設，而第二個是基於經驗證據來自美國和英國（Attanasio和銀行，1998年），也見腳註。
為了達到逼真的發展，在隊伍的發生概率為死亡，我們校準模型再現一個現實的預期壽命估計長度為個人
生活在工業化國家，看到的，例如，國家統計局（2000年）。
.....
5. CONCLUSIONS
Our analysis links adaptation to ageing in the pure consumption model of Grossman with stochastic life-termination.
We show that adaptation has two effects on health demand.
First, the awareness of adaptation makes health investments less attractive,thus yielding a lower optimal health stock over time.
Second, the same awareness gives an incentive for the individual to smoothen planned health stock paths.
The effects of adaptation may, however, not be very high, as a main incentive for demanding health seems to be to prolong life.
Furthermore, it follows that adaptation has effects on health, health investments, and consumption paths being similar to the effects that follow from a higher price on medical care and a higher time preference rate.
However, the smoothening effect observed when analysing adaptation is absent for the same two variables, but show up for a shift in the health depreciation rate.
There is a discussion in the literature of the proper way of doing comparative dynamics in models with many stock variables.
We have, therefore, conducted the analysis on a numerical model, and we show that the effects that arise for the joint development in health and health investments when undertaking comparative dynamics are not changing across models ignoring adaptation and those that do not.
As this analysis concentrates on the effect of adaptation on ageing, i.e., a continuous fall in health, several other interesting problems connected to adaptation is connected to abrupt changes in health.
Also, adaptation as formulated in this work, may not capture all aspects of the phenomena as described in the literature.
There is a lack of formal analyses on adaptation, and future work may provide additional insight.
5。結論
我們的分析鏈接適應老齡化的純消費型的格羅斯曼與隨機生命的終止。
我們證明了適應有兩個作用對健康的需求。
首先，讓健康的認識適應投資的吸引力，從而產生了較低的最佳健康狀態的股票隨著時間的推移。
其次，同樣的認識提供了一種激勵對個人健康計劃，以理順股票路徑。
適應可能的影響，但是，不會很高，作為一個主要誘因似乎是苛刻的健康，延長壽命。
此外，它遵循，適應了對健康的影響，健康投資和消費路徑是類似的效果，請從一個更高的價格在醫療保健和較高的時間偏好率。
然而，平滑的效果進行分析時，發現不存在適應了相同的兩個變量，但出現了轉變，在健康的折舊率。
有一個討論的文學的正確方法做比較動力學模型中的許多股票的變量。
我們有，所以，進行了分析數值模型，我們表明，效果出現的聯合
發展健康和衛生事業的投資時，是不會改變的比較動力學模型忽略了在適應和那些沒有。
由於這種分析集中在適應老齡化的影響，即持續下降的健康，其他一些有趣的問題，以適應連接連接到突然的變化狀況。
此外，作為制定適應這項工作，可能無法捕獲所有方面的現象在文獻中所述。
有一個正式的分析，缺乏適應和未來的工作可能提供額外的洞察力。
論文結論：適應對健康的兩個需求
1.適應會隨時間減少對健康投資的意願，也就是說愈適應，就不會去對健康進行投資。
2.同樣的適應覺知，引起對健康計畫的投入
但是適應並不是延長壽命而引起健康投資的主要因素，即其效果不高，它是與健康投資、消費的路徑相同，即對高價醫藥照顧、以較多時間觀注健康有較高的效果。
