Wangen Knut Reidar, Grepperud Sverre
Department of Health Management and Health Economics, University of Oslo, P.O. box 1089, Blindern, 0318, Oslo, Norway.
BMC Health Serv Res. 2018 Jan 30;18(1):60. doi: 10.1186/s12913-018-2884-5.
Previous works that uses patterns of prior spending to predict future mental health care expenses (utilization models) are mainly concerned with demand (need) variables. In this paper, we introduce supply variables, both individual rater variables and center variables. The aim is to assess these variables' explanatory power, and to investigate whether not accounting for such variables could create biased estimates for the effects of need variables.
We employed an observational study design where the same set of referrals was assessed by a sample of clinicians, thus creating data with a panel structure being particularly relevant for analyzing supply factors. The referrals were obtained from Norwegian Community Mental Health Centers (outpatient services), and the clinicians assessed the referrals with respect to recommended treatment costs and health status.
Supply variables accounted for more than 10% of the total variation and about one third of the explained variation. Two groups of supply variables, individual rater variables and center variables (institutions) were equally important.
Our results confirm that supply factors are important but ignoring such variables, when analyzing demand variables, do not generally seem to produce biased (confounded) coefficients.
以往利用既往支出模式预测未来精神卫生保健费用的研究（利用模型）主要关注需求（需要）变量。在本文中，我们引入了供给变量，包括个体评估者变量和中心变量。目的是评估这些变量的解释力，并调查不考虑此类变量是否会对需求变量的效应产生有偏差的估计。
我们采用了一项观察性研究设计，一组相同的转诊病例由一组临床医生进行评估，从而创建了具有面板结构的数据，这对于分析供给因素特别相关。转诊病例来自挪威社区精神卫生中心（门诊服务），临床医生对转诊病例的推荐治疗费用和健康状况进行评估。
供给变量占总变异的10%以上，占解释变异的约三分之一。两组供给变量，即个体评估者变量和中心变量（机构）同样重要。
我们的结果证实供给因素很重要，但在分析需求变量时忽略此类变量通常似乎不会产生有偏差（混淆）的系数。
