本文旨在探討當央行的目標函數中對通膨和產出的權重有相關時，並且將央行的偏好納入模型之中，對央行其目標通膨機制下之通膨偏誤(inflationary bias)有何影響，最後再比較在不同的目標通膨機制下之通膨偏誤以及預期社會福利。相較於Walsh (1999)的結果，我們得到部份相同、部分不同的結論。以下為三點相異之發現：（1）當央行愈在乎通膨，對通膨有較高的權重，不論在何種目標通膨機制下，其通膨偏誤皆會變小。（2）相較於沒有考慮央行偏好下的政策結果，我們發現考慮央行的偏好後，對通膨偏誤和預期社會福利會有很大的影響。影響的結果則是決定於央行偏好的大小。（3）相較於權衡性政策(discretionary policy)下的通膨偏誤，在非任意政策和宣示政策的模型中加入央行的偏好後，未必有助於降低的通膨偏誤。同樣地，政策比較的結果也是決定於央行偏好的大小。

In this paper, we extend the model of inflation targeting with a penalty borne by the central bank in Walsh (1999) and add the specification of the central bank’s preference in Muscatelli (1998) to study how the weight on inflation, the central bank’s preference affect the inflationary bias under a non-state-contingent policy and an announcement policy. Moreover, we investigate how the expected social welfare varies under a discretionary policy, a non-state-contingent policy, and an announcement policy. We obtain the following findings in contrast with those in Walsh (1999): First, for a non-state-contingent policy and an announcement policy, when the central bank more cares about inflation, the inflationary bias becomes smaller. Second, compared with the inflationary bias under a non-state-contingent policy and an announcement policy without the central bank’s preference, it has a substantial effect on the inflationary bias and the expected social welfare after considering the preference of the central bank into the models. The monetary policy effect depends on the magnitude of the central bank’s preference. Third, adding the preference of the central bank is not definitely beneficial to reduce the inflationary bias and enhance the expected social welfare compared with under a discretionary policy. Similarly, the outcome is dependent on the degree of the central bank’s preference.

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