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Budget deficit and ways of its financing,have different economic implications.The private consumption as one of the major components of the aggregate demand alongside with the private investment are also under the effects of the deficit.The total effects of the deficit can be separated into the primary and secondary effects.The primary effects of the defict is attributed to the causes of the deficit,while the secondary effects is related to the ways of deficit financing.The final effect is the sum of these two effects,which might be positive,negative or zero.The results of the study by the ARDL approach for the time period of 1342-1384 indicates that although the effect of the deficit on private consumption is positive but there is no longrun relationship between them.On the other hand effects of the deficit on private investment is negative.These results also show that the effects of the deficit on investment may last or endure for a long time and therefore it can be said that there is a longrun relationship between deficit and private investment.

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One of the major problems in budgeting is to predict the various kinds of future income precisely as possible. Since tax revenue is very important component in the combination of state income, the present paper considers the forecasting of VAT on gasoline consumption. The main purpose is to achieve an efficient method to forecast gasoline consumption and VAT on it in Iran. Hence, a Hybrid ARIMA- Neural Network model is used to forecast gasoline consumption. After confirming the good performance of this method compared with autoregressive integrated moving average processes(ARIMA), VAT on gasoline consumption is calculated by applying its tax rate. Results indicate that during the years 2013 to 2016, VAT on gasoline consumption will grow by 31.6 percent on average.