親愛的經(jīng)濟(jì)學(xué)家：
Dear Economist,
為什么我要洗車呢？明天它就又臟了！
Why should I wash my car? It will be dirty again tomorrow!
克里斯o史密斯(Chris Smith)
Regards,
漢普郡
Chris Smith,Hampshire
親愛的克里斯：
Dear Chris,
那么，你為什么非得刷牙呢？它們明天也會(huì)再變臟。這種爭論可能會(huì)打動(dòng)某些多愁善感的哲學(xué)家，但經(jīng)濟(jì)學(xué)家會(huì)給出清楚的建議。你無法使自己的車保持得完全像你想象的那么干凈，所以必須在洗車的成本與讓車太臟的成本之間找到平衡。
Why, indeed, should you brush your teeth? They, too, will be dirty tomorrow. Such arguments may impress a certain melancholy breed of philosopher, but economics offers clear advice. You cannot keep your car exactly as clean as you would want, so must balance the costs of washing it against the costs of having it too dirty.
想想一個(gè)類似的問題：在你的錢包里放多少錢合適？放的太多，會(huì)有被盜或遭遇通貨膨脹的風(fēng)險(xiǎn)。放的太少，要錢包就沒有用。由于取現(xiàn)有點(diǎn)兒麻煩，理性消費(fèi)者會(huì)取出超過理想數(shù)額的錢，逐漸把它們花掉，直到錢少于理想數(shù)額，然后再往錢包里放錢。 Consider an analogous problem: how much money to keep in your wallet? Too much and you will suffer from theft or inflation. Too little and the wallet serves no purpose. Since it is troublesome to obtain cash, the rational customer will take out more than is ideal, gradually spend the money until there is less than ideal, and then replenish the wallet.
一段時(shí)間內(nèi)持有現(xiàn)金數(shù)額的曲線，會(huì)像鋸齒一樣，有規(guī)律地上升和下降。如今既然我們有了自動(dòng)取款機(jī)，提現(xiàn)就變得更容易了，所以我們這么做的頻率上升了，使現(xiàn)金余額更趨近于數(shù)額，這樣"鋸齒"就被很完美地抹去了。
A graph of cash held over time would look like a sawtooth, regularly leaping up and sloping down. Now that we have ATMs it is easier to get cash, we do so more often, hold cash balances closer to the optimum, and the saw is finely grained.
這種鋸齒模型可以用到更廣泛的領(lǐng)域。例如，它解釋了你為什么應(yīng)該--像許多人所做的那樣--把頭發(fā)剪得過短，這樣在頭發(fā)長出來時(shí)，平均長度就與應(yīng)該的長度差不多。 The sawtooth model applies more widely. It explains, for example, why you should - as many people do - cut your hair too short, so that as it grows it is on average the correct length.
至于你的車，你必須找出一種辦法，把它洗得比你理想中的狀況干凈，考慮到你的問題，這應(yīng)該不難?？紤]一下包括打蠟和地毯香波的一整套洗車服務(wù)吧。在清洗后一、兩周內(nèi)，車會(huì)干凈得要死，甚至讓你有點(diǎn)兒不好意思，然后你將不耐煩地等著它開始變臟。
As for your car, you must find a way to wash it so that it is cleaner than you would ideally like, which considering your question should not be difficult. Consider a full service wash with wax and carpet shampooing. The car will be so extravagantly, embarrassingly clean that for a week or two after the wash you will be waiting impatiently for the dirt to begin accumulating.
Dear Economist,
為什么我要洗車呢？明天它就又臟了！
Why should I wash my car? It will be dirty again tomorrow!
克里斯o史密斯(Chris Smith)
Regards,
漢普郡
Chris Smith,Hampshire
親愛的克里斯：
Dear Chris,
那么，你為什么非得刷牙呢？它們明天也會(huì)再變臟。這種爭論可能會(huì)打動(dòng)某些多愁善感的哲學(xué)家，但經(jīng)濟(jì)學(xué)家會(huì)給出清楚的建議。你無法使自己的車保持得完全像你想象的那么干凈，所以必須在洗車的成本與讓車太臟的成本之間找到平衡。
Why, indeed, should you brush your teeth? They, too, will be dirty tomorrow. Such arguments may impress a certain melancholy breed of philosopher, but economics offers clear advice. You cannot keep your car exactly as clean as you would want, so must balance the costs of washing it against the costs of having it too dirty.
想想一個(gè)類似的問題：在你的錢包里放多少錢合適？放的太多，會(huì)有被盜或遭遇通貨膨脹的風(fēng)險(xiǎn)。放的太少，要錢包就沒有用。由于取現(xiàn)有點(diǎn)兒麻煩，理性消費(fèi)者會(huì)取出超過理想數(shù)額的錢，逐漸把它們花掉，直到錢少于理想數(shù)額，然后再往錢包里放錢。 Consider an analogous problem: how much money to keep in your wallet? Too much and you will suffer from theft or inflation. Too little and the wallet serves no purpose. Since it is troublesome to obtain cash, the rational customer will take out more than is ideal, gradually spend the money until there is less than ideal, and then replenish the wallet.
一段時(shí)間內(nèi)持有現(xiàn)金數(shù)額的曲線，會(huì)像鋸齒一樣，有規(guī)律地上升和下降。如今既然我們有了自動(dòng)取款機(jī)，提現(xiàn)就變得更容易了，所以我們這么做的頻率上升了，使現(xiàn)金余額更趨近于數(shù)額，這樣"鋸齒"就被很完美地抹去了。
A graph of cash held over time would look like a sawtooth, regularly leaping up and sloping down. Now that we have ATMs it is easier to get cash, we do so more often, hold cash balances closer to the optimum, and the saw is finely grained.
這種鋸齒模型可以用到更廣泛的領(lǐng)域。例如，它解釋了你為什么應(yīng)該--像許多人所做的那樣--把頭發(fā)剪得過短，這樣在頭發(fā)長出來時(shí)，平均長度就與應(yīng)該的長度差不多。 The sawtooth model applies more widely. It explains, for example, why you should - as many people do - cut your hair too short, so that as it grows it is on average the correct length.
至于你的車，你必須找出一種辦法，把它洗得比你理想中的狀況干凈，考慮到你的問題，這應(yīng)該不難?？紤]一下包括打蠟和地毯香波的一整套洗車服務(wù)吧。在清洗后一、兩周內(nèi)，車會(huì)干凈得要死，甚至讓你有點(diǎn)兒不好意思，然后你將不耐煩地等著它開始變臟。
As for your car, you must find a way to wash it so that it is cleaner than you would ideally like, which considering your question should not be difficult. Consider a full service wash with wax and carpet shampooing. The car will be so extravagantly, embarrassingly clean that for a week or two after the wash you will be waiting impatiently for the dirt to begin accumulating.